├── .gitignore ├── algo ├── search │ ├── linear.go │ ├── binary.go │ └── bfs.go ├── sorting │ ├── bubble.go │ ├── selection.go │ ├── insertion.go │ ├── quick.go │ └── merge.go └── recursion │ ├── reverse.go │ ├── fibonacci.go │ └── factorial.go ├── ds ├── queue │ ├── linkedlist_implementation.go │ └── array_implementation.go ├── stack │ ├── linkedlist_implementation.go │ └── array_implementation.go ├── linkedlist │ └── linkedlist.go ├── graph │ └── graph.go ├── bst │ └── tree.go └── avl │ └── avl.go ├── README.md ├── dp └── fibonacci.go ├── CODE_OF_CONDUCT.md └── LICENSE.md /.gitignore: -------------------------------------------------------------------------------- 1 | .idea/ 2 | main.go 3 | -------------------------------------------------------------------------------- /algo/search/linear.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func main() { 6 | arr := []int{4, 2, 5, 8, 3, 9, 7} 7 | fmt.Println(LinearSearch(arr, 6)) 8 | } 9 | 10 | func LinearSearch(arr []int, key int) bool { 11 | for i := 0; i < len(arr); i++ { 12 | if arr[i] == key { 13 | return true 14 | } 15 | } 16 | return false 17 | } 18 | -------------------------------------------------------------------------------- /algo/sorting/bubble.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func bubble(array []int) []int { 6 | for i := 0; i < len(array); i++ { 7 | for j := i + 1; j < len(array); j++ { 8 | if array[i] > array[j] { 9 | array[i], array[j] = array[j], array[i] 10 | } 11 | } 12 | } 13 | return array 14 | } 15 | 16 | func main() { 17 | fmt.Println(bubble([]int{1, 3, 5, 4, 2, 9, 7})) 18 | } 19 | -------------------------------------------------------------------------------- /algo/sorting/selection.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func selection(array []int) []int { 6 | for i := 0; i < len(array); i++ { 7 | min := i 8 | for j := i + 1; j < len(array); j++ { 9 | if array[j] < array[min] { 10 | min = j 11 | } 12 | } 13 | if min != i { 14 | array[i], array[min] = array[min], array[i] 15 | } 16 | } 17 | return array 18 | } 19 | 20 | func main() { 21 | fmt.Println(selection([]int{1, 3, 5, 2, 9, 7})) 22 | } 23 | -------------------------------------------------------------------------------- /algo/recursion/reverse.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func main() { 6 | reverse("this is recursion") 7 | fmt.Printf("\nreverseWithOutput: %v \n", reverseWithOutput("this is recursion")) 8 | 9 | } 10 | 11 | func reverseWithOutput(str string) string { 12 | if len(str) == 1 { 13 | return str 14 | } 15 | return reverseWithOutput(str[1:]) + str[0:1] 16 | } 17 | 18 | func reverse(str string) { 19 | if len(str) == 1 { 20 | fmt.Print(str) 21 | return 22 | } 23 | reverse(str[1:]) 24 | fmt.Print(str[0:1]) 25 | } 26 | -------------------------------------------------------------------------------- /algo/search/binary.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func main() { 6 | arr := []int{2, 3, 4, 5, 7, 8, 9} 7 | fmt.Println(BinarySearch(arr, 6)) 8 | } 9 | 10 | //BinarySearch expects sorted arr 11 | func BinarySearch(arr []int, key int) bool { 12 | if len(arr) == 1 { 13 | return arr[0] == key 14 | } 15 | middle := len(arr) / 2 16 | if arr[middle] == key { 17 | return true 18 | } else if arr[middle] < key { 19 | return BinarySearch(arr[middle+1:], key) 20 | } else { 21 | return BinarySearch(arr[:middle], key) 22 | } 23 | } 24 | -------------------------------------------------------------------------------- /algo/sorting/insertion.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func insertion(array []int) []int { 6 | for i := 1; i < len(array); i++ { 7 | if array[0] > array[i] { 8 | temp := array[i] 9 | copy(array[1:i+1], array[0:i]) 10 | array[0] = temp 11 | } else { 12 | for j := 1; j < i; j++ { 13 | if array[j-1] <= array[i] && array[j] > array[i] { 14 | array[j], array[i] = array[i], array[j] 15 | } 16 | } 17 | } 18 | } 19 | return array 20 | } 21 | func main() { 22 | fmt.Println(insertion([]int{12, 3, 5, 2, 3, 9, 7})) 23 | } 24 | -------------------------------------------------------------------------------- /ds/queue/linkedlist_implementation.go: -------------------------------------------------------------------------------- 1 | package queue 2 | 3 | import ( 4 | "../linkedlist" 5 | 6 | "errors" 7 | ) 8 | 9 | type LinkedQueue struct { 10 | list linkedlist.LinkedList 11 | } 12 | 13 | func (queue *LinkedQueue) Enqueue(value interface{}) { 14 | queue.list.Push(value) 15 | } 16 | 17 | func (queue *LinkedQueue) Dequeue() (value interface{}, err error) { 18 | if queue.list.Length == 0 { 19 | return nil, errors.New("queue is empty") 20 | } 21 | value = queue.list.Shift() 22 | return 23 | } 24 | 25 | func (queue *LinkedQueue) Length() int { 26 | return queue.list.Length 27 | } 28 | -------------------------------------------------------------------------------- /ds/stack/linkedlist_implementation.go: -------------------------------------------------------------------------------- 1 | package stack 2 | 3 | import ( 4 | "../linkedlist" 5 | 6 | "errors" 7 | ) 8 | 9 | type LinkedStack struct { 10 | list linkedlist.LinkedList 11 | } 12 | 13 | func (stack *LinkedStack) Push(value interface{}) bool { 14 | return stack.list.Push(value) 15 | } 16 | 17 | func (stack *LinkedStack) Pop() (value interface{}, err error) { 18 | if stack.list.Length == 0 { 19 | return nil, errors.New("stack is empty") 20 | } 21 | return stack.list.Pop(), nil 22 | } 23 | 24 | func (stack *LinkedStack) Length() (value int) { 25 | return stack.list.Length 26 | } 27 | -------------------------------------------------------------------------------- /ds/stack/array_implementation.go: -------------------------------------------------------------------------------- 1 | package stack 2 | 3 | import "errors" 4 | 5 | type Stack struct { 6 | top int 7 | list []interface{} 8 | } 9 | 10 | func (stack *Stack) Push(value interface{}) { 11 | stack.list = append(stack.list, value) 12 | stack.top++ 13 | } 14 | 15 | func (stack *Stack) Pop() (value interface{}, err error) { 16 | if stack.top <= 0 { 17 | return nil, errors.New("stack is empty") 18 | } 19 | value = stack.list[stack.top-1] 20 | stack.list = stack.list[:stack.top-1] 21 | stack.top-- 22 | return 23 | } 24 | 25 | func (stack *Stack) Length() (value int) { 26 | return stack.top 27 | } 28 | -------------------------------------------------------------------------------- /ds/queue/array_implementation.go: -------------------------------------------------------------------------------- 1 | package queue 2 | 3 | import "errors" 4 | 5 | type ArrayQueue struct { 6 | list []interface{} 7 | length int 8 | } 9 | 10 | func (queue *ArrayQueue) Enqueue(value interface{}) { 11 | queue.list = append(queue.list, value) 12 | queue.length++ 13 | } 14 | 15 | func (queue *ArrayQueue) Dequeue() (value interface{}, err error) { 16 | if queue.length == 0 { 17 | return nil, errors.New("queue is empty") 18 | } 19 | value = queue.list[0] 20 | queue.list = queue.list[1:] 21 | queue.length-- 22 | return 23 | } 24 | 25 | func (queue *ArrayQueue) Length() (value int) { 26 | return queue.length 27 | } 28 | -------------------------------------------------------------------------------- /algo/recursion/fibonacci.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func main() { 6 | fmt.Printf("fibonacciWithLoop: %v \n", fibonacciWithLoop(9)) 7 | fmt.Printf("fibonacciWithRecursion: %v \n", fibonacciWithRecursion(9)) 8 | } 9 | 10 | func fibonacciWithRecursion(index int) int { 11 | if index < 2 { 12 | return index 13 | } 14 | return fibonacciWithRecursion(index-1) + fibonacciWithRecursion(index-2) 15 | } 16 | 17 | func fibonacciWithLoop(index int) int { 18 | first, second := 0, 1 19 | if index < 2 { 20 | return index 21 | } 22 | for i := 2; i < index+1; i++ { 23 | first, second = second, first+second 24 | } 25 | return second 26 | } 27 | -------------------------------------------------------------------------------- /algo/sorting/quick.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "fmt" 5 | "math/rand" 6 | ) 7 | 8 | func quick(array []int) (response []int) { 9 | if len(array) <= 1 { 10 | return array 11 | } 12 | left, right := 0, len(array)-1 13 | pivot := rand.Intn(len(array)) 14 | array[right], array[pivot] = array[pivot], array[right] 15 | for i := 0; i < len(array); i++ { 16 | if array[i] < array[right] { 17 | array[left], array[i] = array[i], array[left] 18 | left++ 19 | } 20 | } 21 | array[left], array[right] = array[right], array[left] 22 | quick(array[:left]) 23 | quick(array[left+1:]) 24 | return array 25 | } 26 | 27 | func main() { 28 | fmt.Println(quick([]int{1, 8, 5, 9, 7, 2, 4})) 29 | } 30 | -------------------------------------------------------------------------------- /algo/recursion/factorial.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func main() { 6 | fmt.Printf("factorialWithRecursion: %v \n", factorialWithRecursion(5)) 7 | fmt.Printf("factorialWithLoop: %v \n", factorialWithLoop(5)) 8 | } 9 | 10 | //factorialWithRecursion returns 1 for numbers less than 2 or else the factorial using recursion 11 | func factorialWithRecursion(num int) int { 12 | if num < 2 { 13 | return 1 14 | } 15 | return num * factorialWithRecursion(num-1) 16 | } 17 | 18 | //factorialWithLoop returns 1 for numbers less than 2 or else the factorial using loop 19 | func factorialWithLoop(num int) int { 20 | var factorial = 1 21 | for ; num > 1; num-- { 22 | factorial *= num 23 | } 24 | return factorial 25 | } 26 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Implementation of Data Strucutures and Algorithms with Golang 2 | 3 | 4 | ### Data Strucutures 5 | * Stack 6 | * Array implementation 7 | * LinkedList implementation 8 | * Queue 9 | * Array implementation 10 | * LinkedList implementation 11 | * LinkedList 12 | * BST(Binary Search Tree) 13 | * AVL Tree 14 | * Graph (Undirected Unweighted Graph) _Adjacency list implementation_ 15 | 16 | ### Algorithms 17 | * Recursion 18 | * Search 19 | * Linear Search 20 | * Binary Search 21 | * BFS (Breadth-first search) 22 | * DFS _Implemented in BST_ 23 | | Pre-order | In-order | Post-order | 24 | * Sort 25 | * Bubble Sort 26 | * Selection Sort 27 | * Insertion Sort 28 | * Merge Sort 29 | * Quick Sort 30 | 31 | -------------------------------------------------------------------------------- /dp/fibonacci.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | var calculation int 6 | 7 | func main() { 8 | fibO := fibonacci() 9 | fmt.Println(fibO(10)) 10 | fmt.Println(calculation) 11 | } 12 | 13 | // fibonacci function uses dynamic programming principle 14 | func fibonacci() func(n int) int { 15 | var fib func(int) int 16 | var cache = map[int]int{} 17 | fib = func(n int) int { 18 | calculation++ 19 | if result, ok := cache[n]; ok { 20 | return result 21 | } 22 | if n < 2 { 23 | return n 24 | } 25 | cache[n] = fib(n-1) + fib(n-2) 26 | return cache[n] 27 | } 28 | return fib 29 | } 30 | 31 | //fib function is simple implementation 32 | func fib(n int) int { 33 | calculation++ 34 | if n < 2 { 35 | return n 36 | } 37 | return fib(n-1) + fib(n-2) 38 | } 39 | -------------------------------------------------------------------------------- /algo/sorting/merge.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import "fmt" 4 | 5 | func merge(array []int) []int { 6 | if len(array) == 1 { 7 | return array 8 | } 9 | middle := len(array) / 2 10 | left := array[:middle] 11 | right := array[middle:] 12 | 13 | array = mergesort(array, merge(left), merge(right)) 14 | return array 15 | } 16 | 17 | func mergesort(array []int, left []int, right []int) []int { 18 | var response []int 19 | lIndex, rIndex := 0, 0 20 | for lIndex < len(left) || rIndex < len(right) { 21 | if lIndex < len(left) && (rIndex == len(right) || left[lIndex] < right[rIndex]) { 22 | response = append(response, left[lIndex]) 23 | lIndex++ 24 | } else { 25 | response = append(response, right[rIndex]) 26 | rIndex++ 27 | } 28 | } 29 | return response 30 | } 31 | 32 | func main() { 33 | fmt.Println(merge([]int{1, 3, 5, 2, 4, 3, 9, 7})) 34 | } 35 | -------------------------------------------------------------------------------- /algo/search/bfs.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "../../ds/bst" 5 | 6 | "fmt" 7 | ) 8 | 9 | /* 10 | For array representation: [4,2,7,1,3,5,9] 11 | 12 | 4 13 | / \ 14 | (2*n + 1) 2 7 (2*n +2) 15 | / \ / \ 16 | 1 3 5 9 17 | 18 | */ 19 | 20 | func main() { 21 | // using actual BST 22 | var tree = new(bst.BST) 23 | tree.Add(4) 24 | tree.Add(2) 25 | tree.Add(7) 26 | tree.Add(1) 27 | tree.Add(5) 28 | tree.Add(3) 29 | tree.Add(9) 30 | fmt.Println(tree.BFSearch(1)) 31 | 32 | // using array representation of tree 33 | var arr = []int{4, 2, 7, 1, 3, 5, 9} 34 | fmt.Println(BFS(arr, 1)) 35 | } 36 | 37 | //BFS using array linear traversal as (2*n + 1) & (2*n + 2) can be achieved this way also(easier too :) ) . 38 | func BFS(arr []int, key int) bool { 39 | for i := 0; i < len(arr); i++ { 40 | if arr[i] == key { 41 | return true 42 | } 43 | } 44 | return false 45 | } 46 | -------------------------------------------------------------------------------- /ds/linkedlist/linkedlist.go: -------------------------------------------------------------------------------- 1 | package linkedlist 2 | 3 | type node struct { 4 | value interface{} 5 | next *node 6 | } 7 | type LinkedList struct { 8 | root *node 9 | Length int 10 | } 11 | 12 | func (list *LinkedList) Insert(value interface{}, position int) bool { 13 | if position > list.Length { 14 | return false 15 | } else if position == 0 { 16 | newNode := &node{ 17 | value: value, 18 | next: list.root, 19 | } 20 | list.root = newNode 21 | list.Length++ 22 | } else { 23 | currentNode := list.root 24 | currentIndex := 0 25 | for ; currentIndex < position-1; currentIndex++ { 26 | currentNode = currentNode.next 27 | } 28 | newNode := &node{ 29 | value: value, 30 | next: currentNode.next, 31 | } 32 | currentNode.next = newNode 33 | list.Length++ 34 | } 35 | return true 36 | } 37 | 38 | func (list *LinkedList) Push(value interface{}) bool { 39 | return list.Insert(value, list.Length) 40 | } 41 | 42 | func (list *LinkedList) Unshift(value interface{}) bool { 43 | return list.Insert(value, 0) 44 | } 45 | 46 | func (list *LinkedList) Remove(position int) (value interface{}) { 47 | if list.Length == 0 || position >= list.Length { 48 | return nil 49 | } 50 | if position == 0 { 51 | value = list.root.value 52 | list.root = list.root.next 53 | list.Length-- 54 | } else { 55 | currentNode := list.root 56 | currentIndex := 0 57 | for ; currentIndex < position-1; currentIndex++ { 58 | currentNode = currentNode.next 59 | } 60 | value = currentNode.next.value 61 | currentNode.next = currentNode.next.next 62 | list.Length-- 63 | } 64 | return 65 | } 66 | 67 | func (list *LinkedList) Pop() interface{} { 68 | return list.Remove(list.Length - 1) 69 | } 70 | 71 | func (list *LinkedList) Shift() interface{} { 72 | return list.Remove(0) 73 | } 74 | 75 | func (list *LinkedList) Traverse() (response []interface{}) { 76 | currentNode := list.root 77 | for currentNode != nil { 78 | response = append(response, currentNode.value) 79 | currentNode = currentNode.next 80 | } 81 | return 82 | } 83 | -------------------------------------------------------------------------------- /ds/graph/graph.go: -------------------------------------------------------------------------------- 1 | package graph 2 | 3 | type graph struct { 4 | Length int 5 | AdjacentList map[interface{}][]interface{} 6 | } 7 | 8 | func New() *graph { 9 | return &graph{ 10 | Length: 0, 11 | AdjacentList: make(map[interface{}][]interface{}), 12 | } 13 | } 14 | 15 | func (graph *graph) AddNode(name interface{}) { 16 | graph.AdjacentList[name] = nil 17 | graph.Length++ 18 | } 19 | 20 | func (graph *graph) RemoveNode(name interface{}) { 21 | if graph.Length == 0 { 22 | return 23 | } 24 | //clear all connections with the node to be deleted 25 | for _, node := range graph.AdjacentList[name] { 26 | for i, adjacentNode := range graph.AdjacentList[node] { 27 | if adjacentNode == name { 28 | graph.AdjacentList[node][i] = graph.AdjacentList[node][len(graph.AdjacentList[node])-1] 29 | graph.AdjacentList[node] = graph.AdjacentList[node][:len(graph.AdjacentList[node])-1] 30 | } 31 | } 32 | } 33 | delete(graph.AdjacentList, name) 34 | graph.Length-- 35 | } 36 | 37 | func (graph *graph) AddEdge(nodeOne, nodeTwo interface{}) { 38 | graph.AdjacentList[nodeOne] = append(graph.AdjacentList[nodeOne], nodeTwo) 39 | graph.AdjacentList[nodeTwo] = append(graph.AdjacentList[nodeTwo], nodeOne) 40 | } 41 | 42 | func (graph *graph) RemoveEdge(nodeOne, nodeTwo interface{}) { 43 | //removes connection from nodeOne -> nodeTwo 44 | for i, node := range graph.AdjacentList[nodeOne] { 45 | if node == nodeTwo { 46 | graph.AdjacentList[nodeOne][i] = graph.AdjacentList[nodeOne][len(graph.AdjacentList[nodeOne])-1] 47 | graph.AdjacentList[nodeOne] = graph.AdjacentList[nodeOne][:len(graph.AdjacentList[nodeOne])-1] 48 | } 49 | } 50 | //removes connection from nodeTwo -> nodeOne 51 | for i, node := range graph.AdjacentList[nodeTwo] { 52 | if node == nodeOne { 53 | graph.AdjacentList[nodeTwo][i] = graph.AdjacentList[nodeTwo][len(graph.AdjacentList[nodeTwo])-1] 54 | graph.AdjacentList[nodeTwo] = graph.AdjacentList[nodeTwo][:len(graph.AdjacentList[nodeTwo])-1] 55 | } 56 | } 57 | } 58 | 59 | func (graph *graph) Show() map[interface{}][]interface{} { 60 | return graph.AdjacentList 61 | } 62 | -------------------------------------------------------------------------------- /CODE_OF_CONDUCT.md: -------------------------------------------------------------------------------- 1 | # Contributor Covenant Code of Conduct 2 | 3 | ## Our Pledge 4 | 5 | In the interest of fostering an open and welcoming environment, we as 6 | contributors and maintainers pledge to making participation in our project and 7 | our community a harassment-free experience for everyone, regardless of age, body 8 | size, disability, ethnicity, sex characteristics, gender identity and expression, 9 | level of experience, education, socio-economic status, nationality, personal 10 | appearance, race, religion, or sexual identity and orientation. 11 | 12 | ## Our Standards 13 | 14 | Examples of behavior that contributes to creating a positive environment 15 | include: 16 | 17 | * Using welcoming and inclusive language 18 | * Being respectful of differing viewpoints and experiences 19 | * Gracefully accepting constructive criticism 20 | * Focusing on what is best for the community 21 | * Showing empathy towards other community members 22 | 23 | Examples of unacceptable behavior by participants include: 24 | 25 | * The use of sexualized language or imagery and unwelcome sexual attention or 26 | advances 27 | * Trolling, insulting/derogatory comments, and personal or political attacks 28 | * Public or private harassment 29 | * Publishing others' private information, such as a physical or electronic 30 | address, without explicit permission 31 | * Other conduct which could reasonably be considered inappropriate in a 32 | professional setting 33 | 34 | ## Our Responsibilities 35 | 36 | Project maintainers are responsible for clarifying the standards of acceptable 37 | behavior and are expected to take appropriate and fair corrective action in 38 | response to any instances of unacceptable behavior. 39 | 40 | Project maintainers have the right and responsibility to remove, edit, or 41 | reject comments, commits, code, wiki edits, issues, and other contributions 42 | that are not aligned to this Code of Conduct, or to ban temporarily or 43 | permanently any contributor for other behaviors that they deem inappropriate, 44 | threatening, offensive, or harmful. 45 | 46 | ## Scope 47 | 48 | This Code of Conduct applies both within project spaces and in public spaces 49 | when an individual is representing the project or its community. Examples of 50 | representing a project or community include using an official project e-mail 51 | address, posting via an official social media account, or acting as an appointed 52 | representative at an online or offline event. Representation of a project may be 53 | further defined and clarified by project maintainers. 54 | 55 | ## Enforcement 56 | 57 | Instances of abusive, harassing, or otherwise unacceptable behavior may be 58 | reported by contacting the project team at mailmeonpunit@gmail.com. All 59 | complaints will be reviewed and investigated and will result in a response that 60 | is deemed necessary and appropriate to the circumstances. The project team is 61 | obligated to maintain confidentiality with regard to the reporter of an incident. 62 | Further details of specific enforcement policies may be posted separately. 63 | 64 | Project maintainers who do not follow or enforce the Code of Conduct in good 65 | faith may face temporary or permanent repercussions as determined by other 66 | members of the project's leadership. 67 | 68 | ## Attribution 69 | 70 | This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, 71 | available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html 72 | 73 | [homepage]: https://www.contributor-covenant.org 74 | 75 | For answers to common questions about this code of conduct, see 76 | https://www.contributor-covenant.org/faq 77 | -------------------------------------------------------------------------------- /ds/bst/tree.go: -------------------------------------------------------------------------------- 1 | package bst 2 | 3 | import "../queue" 4 | 5 | type node struct { 6 | value int 7 | left *node 8 | right *node 9 | } 10 | 11 | type BST struct { 12 | root *node 13 | Length int 14 | } 15 | 16 | func (tree *BST) Add(value int) { 17 | var currentNode, parentNode *node 18 | if tree.root == nil { 19 | tree.root = &node{ 20 | value: value, 21 | left: nil, 22 | right: nil, 23 | } 24 | tree.Length++ 25 | } else { 26 | currentNode = tree.root 27 | for currentNode != nil { 28 | parentNode = currentNode 29 | if currentNode.value > value { 30 | currentNode = currentNode.left 31 | } else { 32 | currentNode = currentNode.right 33 | } 34 | } 35 | if parentNode.value < value { 36 | parentNode.right = &node{ 37 | value: value, 38 | left: nil, 39 | right: nil, 40 | } 41 | } else { 42 | parentNode.left = &node{ 43 | value: value, 44 | left: nil, 45 | right: nil, 46 | } 47 | } 48 | } 49 | } 50 | 51 | func (tree *BST) Remove(value int) { 52 | var replacer, replacerParent, parentNode *node 53 | currentNode := tree.root 54 | for currentNode != nil { 55 | if currentNode.value == value { 56 | if currentNode.right == nil { 57 | if parentNode.value > currentNode.value { 58 | parentNode.left = nil 59 | } else { 60 | parentNode.right = nil 61 | } 62 | } else { 63 | replacer, replacerParent = currentNode.right.Min() 64 | if replacerParent != nil { 65 | replacerParent.left = replacer.right 66 | } 67 | replacer.left = currentNode.left 68 | replacer.right = currentNode.right 69 | if currentNode != tree.root { 70 | if parentNode.value > currentNode.value { 71 | parentNode.left = replacer 72 | } else { 73 | parentNode.right = replacer 74 | } 75 | } else { 76 | tree.root = replacer 77 | } 78 | } 79 | return 80 | } else if currentNode.value < value { 81 | parentNode = currentNode 82 | currentNode = currentNode.right 83 | } else { 84 | parentNode = currentNode 85 | currentNode = currentNode.left 86 | } 87 | } 88 | } 89 | 90 | func (node *node) Min() (minNode, parentNode *node) { 91 | minNode = node 92 | for minNode.left != nil { 93 | parentNode = minNode 94 | minNode = minNode.left 95 | } 96 | return 97 | } 98 | 99 | func (tree *BST) PreOrderTraverse() (values []int) { 100 | return tree.root.PreOrderTraverse() 101 | } 102 | 103 | func (node *node) PreOrderTraverse() (values []int) { 104 | currentNode := node 105 | values = append(values, currentNode.value) 106 | if currentNode.left != nil { 107 | values = append(values, currentNode.left.PreOrderTraverse()...) 108 | } 109 | if currentNode.right != nil { 110 | values = append(values, currentNode.right.PreOrderTraverse()...) 111 | } 112 | return 113 | } 114 | 115 | func (tree *BST) InOrderTraverse() (value []int) { 116 | return tree.root.InOrderTraverse() 117 | } 118 | 119 | func (node *node) InOrderTraverse() (values []int) { 120 | currentNode := node 121 | if currentNode.left != nil { 122 | values = append(values, currentNode.left.InOrderTraverse()...) 123 | } 124 | values = append(values, currentNode.value) 125 | if currentNode.right != nil { 126 | values = append(values, currentNode.right.InOrderTraverse()...) 127 | } 128 | return 129 | } 130 | 131 | func (tree *BST) PostOrderTraverse() (value []int) { 132 | return tree.root.PostOrderTraverse() 133 | } 134 | 135 | func (node *node) PostOrderTraverse() (values []int) { 136 | currentNode := node 137 | if currentNode.left != nil { 138 | values = append(values, currentNode.left.PostOrderTraverse()...) 139 | } 140 | if currentNode.right != nil { 141 | values = append(values, currentNode.right.PostOrderTraverse()...) 142 | } 143 | values = append(values, currentNode.value) 144 | return 145 | } 146 | 147 | func (tree *BST) BFTraverse() (values []int) { 148 | var queue = new(queue.LinkedQueue) 149 | queue.Enqueue(tree.root) 150 | for queue.Length() != 0 { 151 | firstNode, _ := queue.Dequeue() 152 | currentNode := firstNode.(*node) 153 | values = append(values, currentNode.value) 154 | if currentNode.left != nil { 155 | queue.Enqueue(currentNode.left) 156 | } 157 | if currentNode.right != nil { 158 | queue.Enqueue(currentNode.right) 159 | } 160 | } 161 | return values 162 | } 163 | 164 | func (tree *BST) BFSearch(key int) bool { 165 | var queue = new(queue.LinkedQueue) 166 | queue.Enqueue(tree.root) 167 | for queue.Length() != 0 { 168 | firstNode, _ := queue.Dequeue() 169 | currentNode := firstNode.(*node) 170 | if currentNode.value == key { 171 | return true 172 | } 173 | if currentNode.left != nil { 174 | queue.Enqueue(currentNode.left) 175 | } 176 | if currentNode.right != nil { 177 | queue.Enqueue(currentNode.right) 178 | } 179 | } 180 | return false 181 | } 182 | -------------------------------------------------------------------------------- /ds/avl/avl.go: -------------------------------------------------------------------------------- 1 | package avl 2 | 3 | type Node struct { 4 | value int 5 | left *Node 6 | right *Node 7 | } 8 | 9 | type AVL struct { 10 | root *Node 11 | } 12 | 13 | func (avl *AVL) Insert(value int) { 14 | if avl.root == nil { 15 | avl.root = &Node{ 16 | value: value, 17 | } 18 | } else { 19 | avl.root = avl.root.Insert(value) 20 | avl.root = avl.root.Balance() 21 | } 22 | } 23 | 24 | /* 25 | Successor returns successor node and parent of successor as: 26 | Case 1:returns nil, nil if callee has no right child 27 | Case 2:returns node.right, node if successor is right node 28 | Case 3:returns successorNode, successorParent if successor is right node's child 29 | */ 30 | func (node *Node) Successor() (successor, parent *Node) { 31 | parent = node 32 | successor = node.right 33 | for successor != nil && successor.left != nil { 34 | if successor.left == nil { 35 | break 36 | } 37 | parent = successor 38 | successor = successor.left 39 | } 40 | return successor, parent 41 | } 42 | 43 | /* 44 | Remove of *AVL handle head removal cases, or calls Remove of *Node 45 | Case 1: right node is successor 46 | Case 2: right's child node is successor 47 | Case 3: left node is successor 48 | */ 49 | func (avl *AVL) Remove(value int) { 50 | if avl.root.value == value { 51 | replacer, replacerParent := avl.root.Successor() 52 | if replacer != nil { 53 | replacer.left = avl.root.left 54 | if replacerParent != avl.root { 55 | replacerParent.left = replacer.right 56 | replacer.right = avl.root.right 57 | } 58 | avl.root = replacer 59 | avl.root = avl.root.Balance() 60 | } else { 61 | avl.root = avl.root.left 62 | } 63 | } else { 64 | avl.root = avl.root.Remove(value, nil) 65 | } 66 | } 67 | 68 | /* 69 | Remove of *Node handle cases with non-head node removal 70 | Case 1: having only right node 71 | Case 2: having successor other than right node with no child 72 | Case 3: having successor with right child 73 | */ 74 | func (node *Node) Remove(value int, parentNode *Node) *Node { 75 | if node.value == value { 76 | if node.right == nil { 77 | if parentNode.value > node.value { 78 | parentNode.left = nil 79 | } else { 80 | parentNode.right = nil 81 | } 82 | } else { 83 | replacer, replacerParent := node.Successor() 84 | replacer.left = node.left 85 | if replacerParent != node { 86 | replacer.right = node.right 87 | replacerParent.left = replacer.right 88 | } 89 | if parentNode.value > node.value { 90 | parentNode.left = replacer 91 | } else { 92 | parentNode.right = replacer 93 | } 94 | } 95 | } else if node.value < value { 96 | parentNode = node 97 | _ = node.right.Remove(value, node) 98 | parentNode = parentNode.Balance() 99 | } else { 100 | parentNode = node 101 | _ = node.left.Remove(value, node) 102 | parentNode = parentNode.Balance() 103 | } 104 | return parentNode 105 | } 106 | 107 | func (avl *AVL) Traverse() []int { 108 | return avl.root.Traverse() 109 | } 110 | 111 | // Traverse returns []int with Pre-Order traversal 112 | func (node *Node) Traverse() (nodes []int) { 113 | if node == nil { 114 | return 115 | } 116 | nodes = append(nodes, node.value) 117 | nodes = append(nodes, node.left.Traverse()...) 118 | nodes = append(nodes, node.right.Traverse()...) 119 | return nodes 120 | } 121 | 122 | // Balance returns the rearrange node with maximum depth difference of 1 for callee 123 | func (node *Node) Balance() *Node { 124 | height := node.left.Height() - node.right.Height() 125 | if height < -1 { 126 | // left rotation required 127 | diff := node.right.left.Height() - node.right.right.Height() 128 | if diff > 0 { 129 | node.right = node.right.RightRotate() 130 | } 131 | node = node.LeftRotate() 132 | } 133 | if height > 1 { 134 | // right rotation required 135 | diff := node.left.left.Height() - node.left.right.Height() 136 | if diff < 0 { 137 | node.left = node.left.LeftRotate() 138 | } 139 | node = node.RightRotate() 140 | } 141 | return node 142 | } 143 | 144 | // Height returns the maximum depth of callee node 145 | func (node *Node) Height() int { 146 | var leftHeight, rightHeight int 147 | if node == nil { 148 | return 0 149 | } 150 | leftHeight = node.left.Height() 151 | rightHeight = node.right.Height() 152 | if leftHeight > rightHeight { 153 | return leftHeight + 1 154 | } 155 | return rightHeight + 1 156 | } 157 | 158 | func (node *Node) LeftRotate() *Node { 159 | node.right, node.right.left, node = node.right.left, node, node.right 160 | return node 161 | } 162 | 163 | func (node *Node) RightRotate() *Node { 164 | node.left, node.left.right, node = node.left.right, node, node.left 165 | return node 166 | } 167 | 168 | func (node *Node) Insert(value int) *Node { 169 | if value < node.value { 170 | if node.left != nil { 171 | node.left = node.left.Insert(value) 172 | node = node.Balance() 173 | } else { 174 | node.left = &Node{ 175 | value: value, 176 | } 177 | } 178 | } else { 179 | if node.right != nil { 180 | node.right = node.right.Insert(value) 181 | node = node.Balance() 182 | } else { 183 | node.right = &Node{ 184 | value: value, 185 | } 186 | } 187 | } 188 | return node 189 | } 190 | -------------------------------------------------------------------------------- /LICENSE.md: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. We, the Free Software Foundation, use the 18 | GNU General Public License for most of our software; it applies also to 19 | any other work released this way by its authors. You can apply it to 20 | your programs, too. 21 | 22 | When we speak of free software, we are referring to freedom, not 23 | price. Our General Public Licenses are designed to make sure that you 24 | have the freedom to distribute copies of free software (and charge for 25 | them if you wish), that you receive source code or can get it if you 26 | want it, that you can change the software or use pieces of it in new 27 | free programs, and that you know you can do these things. 28 | 29 | To protect your rights, we need to prevent others from denying you 30 | these rights or asking you to surrender the rights. Therefore, you have 31 | certain responsibilities if you distribute copies of the software, or if 32 | you modify it: responsibilities to respect the freedom of others. 33 | 34 | For example, if you distribute copies of such a program, whether 35 | gratis or for a fee, you must pass on to the recipients the same 36 | freedoms that you received. You must make sure that they, too, receive 37 | or can get the source code. And you must show them these terms so they 38 | know their rights. 39 | 40 | Developers that use the GNU GPL protect your rights with two steps: 41 | (1) assert copyright on the software, and (2) offer you this License 42 | giving you legal permission to copy, distribute and/or modify it. 43 | 44 | For the developers' and authors' protection, the GPL clearly explains 45 | that there is no warranty for this free software. For both users' and 46 | authors' sake, the GPL requires that modified versions be marked as 47 | changed, so that their problems will not be attributed erroneously to 48 | authors of previous versions. 49 | 50 | Some devices are designed to deny users access to install or run 51 | modified versions of the software inside them, although the manufacturer 52 | can do so. This is fundamentally incompatible with the aim of 53 | protecting users' freedom to change the software. The systematic 54 | pattern of such abuse occurs in the area of products for individuals to 55 | use, which is precisely where it is most unacceptable. Therefore, we 56 | have designed this version of the GPL to prohibit the practice for those 57 | products. If such problems arise substantially in other domains, we 58 | stand ready to extend this provision to those domains in future versions 59 | of the GPL, as needed to protect the freedom of users. 60 | 61 | Finally, every program is threatened constantly by software patents. 62 | States should not allow patents to restrict development and use of 63 | software on general-purpose computers, but in those that do, we wish to 64 | avoid the special danger that patents applied to a free program could 65 | make it effectively proprietary. To prevent this, the GPL assures that 66 | patents cannot be used to render the program non-free. 67 | 68 | The precise terms and conditions for copying, distribution and 69 | modification follow. 70 | 71 | TERMS AND CONDITIONS 72 | 73 | 0. Definitions. 74 | 75 | "This License" refers to version 3 of the GNU General Public License. 76 | 77 | "Copyright" also means copyright-like laws that apply to other kinds of 78 | works, such as semiconductor masks. 79 | 80 | "The Program" refers to any copyrightable work licensed under this 81 | License. Each licensee is addressed as "you". "Licensees" and 82 | "recipients" may be individuals or organizations. 83 | 84 | To "modify" a work means to copy from or adapt all or part of the work 85 | in a fashion requiring copyright permission, other than the making of an 86 | exact copy. The resulting work is called a "modified version" of the 87 | earlier work or a work "based on" the earlier work. 88 | 89 | A "covered work" means either the unmodified Program or a work based 90 | on the Program. 91 | 92 | To "propagate" a work means to do anything with it that, without 93 | permission, would make you directly or secondarily liable for 94 | infringement under applicable copyright law, except executing it on a 95 | computer or modifying a private copy. Propagation includes copying, 96 | distribution (with or without modification), making available to the 97 | public, and in some countries other activities as well. 98 | 99 | To "convey" a work means any kind of propagation that enables other 100 | parties to make or receive copies. Mere interaction with a user through 101 | a computer network, with no transfer of a copy, is not conveying. 102 | 103 | An interactive user interface displays "Appropriate Legal Notices" 104 | to the extent that it includes a convenient and prominently visible 105 | feature that (1) displays an appropriate copyright notice, and (2) 106 | tells the user that there is no warranty for the work (except to the 107 | extent that warranties are provided), that licensees may convey the 108 | work under this License, and how to view a copy of this License. If 109 | the interface presents a list of user commands or options, such as a 110 | menu, a prominent item in the list meets this criterion. 111 | 112 | 1. Source Code. 113 | 114 | The "source code" for a work means the preferred form of the work 115 | for making modifications to it. "Object code" means any non-source 116 | form of a work. 117 | 118 | A "Standard Interface" means an interface that either is an official 119 | standard defined by a recognized standards body, or, in the case of 120 | interfaces specified for a particular programming language, one that 121 | is widely used among developers working in that language. 122 | 123 | The "System Libraries" of an executable work include anything, other 124 | than the work as a whole, that (a) is included in the normal form of 125 | packaging a Major Component, but which is not part of that Major 126 | Component, and (b) serves only to enable use of the work with that 127 | Major Component, or to implement a Standard Interface for which an 128 | implementation is available to the public in source code form. A 129 | "Major Component", in this context, means a major essential component 130 | (kernel, window system, and so on) of the specific operating system 131 | (if any) on which the executable work runs, or a compiler used to 132 | produce the work, or an object code interpreter used to run it. 133 | 134 | The "Corresponding Source" for a work in object code form means all 135 | the source code needed to generate, install, and (for an executable 136 | work) run the object code and to modify the work, including scripts to 137 | control those activities. However, it does not include the work's 138 | System Libraries, or general-purpose tools or generally available free 139 | programs which are used unmodified in performing those activities but 140 | which are not part of the work. For example, Corresponding Source 141 | includes interface definition files associated with source files for 142 | the work, and the source code for shared libraries and dynamically 143 | linked subprograms that the work is specifically designed to require, 144 | such as by intimate data communication or control flow between those 145 | subprograms and other parts of the work. 146 | 147 | The Corresponding Source need not include anything that users 148 | can regenerate automatically from other parts of the Corresponding 149 | Source. 150 | 151 | The Corresponding Source for a work in source code form is that 152 | same work. 153 | 154 | 2. Basic Permissions. 155 | 156 | All rights granted under this License are granted for the term of 157 | copyright on the Program, and are irrevocable provided the stated 158 | conditions are met. This License explicitly affirms your unlimited 159 | permission to run the unmodified Program. The output from running a 160 | covered work is covered by this License only if the output, given its 161 | content, constitutes a covered work. This License acknowledges your 162 | rights of fair use or other equivalent, as provided by copyright law. 163 | 164 | You may make, run and propagate covered works that you do not 165 | convey, without conditions so long as your license otherwise remains 166 | in force. You may convey covered works to others for the sole purpose 167 | of having them make modifications exclusively for you, or provide you 168 | with facilities for running those works, provided that you comply with 169 | the terms of this License in conveying all material for which you do 170 | not control copyright. Those thus making or running the covered works 171 | for you must do so exclusively on your behalf, under your direction 172 | and control, on terms that prohibit them from making any copies of 173 | your copyrighted material outside their relationship with you. 174 | 175 | Conveying under any other circumstances is permitted solely under 176 | the conditions stated below. Sublicensing is not allowed; section 10 177 | makes it unnecessary. 178 | 179 | 3. Protecting Users' Legal Rights From Anti-Circumvention Law. 180 | 181 | No covered work shall be deemed part of an effective technological 182 | measure under any applicable law fulfilling obligations under article 183 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or 184 | similar laws prohibiting or restricting circumvention of such 185 | measures. 186 | 187 | When you convey a covered work, you waive any legal power to forbid 188 | circumvention of technological measures to the extent such circumvention 189 | is effected by exercising rights under this License with respect to 190 | the covered work, and you disclaim any intention to limit operation or 191 | modification of the work as a means of enforcing, against the work's 192 | users, your or third parties' legal rights to forbid circumvention of 193 | technological measures. 194 | 195 | 4. Conveying Verbatim Copies. 196 | 197 | You may convey verbatim copies of the Program's source code as you 198 | receive it, in any medium, provided that you conspicuously and 199 | appropriately publish on each copy an appropriate copyright notice; 200 | keep intact all notices stating that this License and any 201 | non-permissive terms added in accord with section 7 apply to the code; 202 | keep intact all notices of the absence of any warranty; and give all 203 | recipients a copy of this License along with the Program. 204 | 205 | You may charge any price or no price for each copy that you convey, 206 | and you may offer support or warranty protection for a fee. 207 | 208 | 5. Conveying Modified Source Versions. 209 | 210 | You may convey a work based on the Program, or the modifications to 211 | produce it from the Program, in the form of source code under the 212 | terms of section 4, provided that you also meet all of these conditions: 213 | 214 | a) The work must carry prominent notices stating that you modified 215 | it, and giving a relevant date. 216 | 217 | b) The work must carry prominent notices stating that it is 218 | released under this License and any conditions added under section 219 | 7. This requirement modifies the requirement in section 4 to 220 | "keep intact all notices". 221 | 222 | c) You must license the entire work, as a whole, under this 223 | License to anyone who comes into possession of a copy. This 224 | License will therefore apply, along with any applicable section 7 225 | additional terms, to the whole of the work, and all its parts, 226 | regardless of how they are packaged. This License gives no 227 | permission to license the work in any other way, but it does not 228 | invalidate such permission if you have separately received it. 229 | 230 | d) If the work has interactive user interfaces, each must display 231 | Appropriate Legal Notices; however, if the Program has interactive 232 | interfaces that do not display Appropriate Legal Notices, your 233 | work need not make them do so. 234 | 235 | A compilation of a covered work with other separate and independent 236 | works, which are not by their nature extensions of the covered work, 237 | and which are not combined with it such as to form a larger program, 238 | in or on a volume of a storage or distribution medium, is called an 239 | "aggregate" if the compilation and its resulting copyright are not 240 | used to limit the access or legal rights of the compilation's users 241 | beyond what the individual works permit. Inclusion of a covered work 242 | in an aggregate does not cause this License to apply to the other 243 | parts of the aggregate. 244 | 245 | 6. Conveying Non-Source Forms. 246 | 247 | You may convey a covered work in object code form under the terms 248 | of sections 4 and 5, provided that you also convey the 249 | machine-readable Corresponding Source under the terms of this License, 250 | in one of these ways: 251 | 252 | a) Convey the object code in, or embodied in, a physical product 253 | (including a physical distribution medium), accompanied by the 254 | Corresponding Source fixed on a durable physical medium 255 | customarily used for software interchange. 256 | 257 | b) Convey the object code in, or embodied in, a physical product 258 | (including a physical distribution medium), accompanied by a 259 | written offer, valid for at least three years and valid for as 260 | long as you offer spare parts or customer support for that product 261 | model, to give anyone who possesses the object code either (1) a 262 | copy of the Corresponding Source for all the software in the 263 | product that is covered by this License, on a durable physical 264 | medium customarily used for software interchange, for a price no 265 | more than your reasonable cost of physically performing this 266 | conveying of source, or (2) access to copy the 267 | Corresponding Source from a network server at no charge. 268 | 269 | c) Convey individual copies of the object code with a copy of the 270 | written offer to provide the Corresponding Source. This 271 | alternative is allowed only occasionally and noncommercially, and 272 | only if you received the object code with such an offer, in accord 273 | with subsection 6b. 274 | 275 | d) Convey the object code by offering access from a designated 276 | place (gratis or for a charge), and offer equivalent access to the 277 | Corresponding Source in the same way through the same place at no 278 | further charge. You need not require recipients to copy the 279 | Corresponding Source along with the object code. If the place to 280 | copy the object code is a network server, the Corresponding Source 281 | may be on a different server (operated by you or a third party) 282 | that supports equivalent copying facilities, provided you maintain 283 | clear directions next to the object code saying where to find the 284 | Corresponding Source. Regardless of what server hosts the 285 | Corresponding Source, you remain obligated to ensure that it is 286 | available for as long as needed to satisfy these requirements. 287 | 288 | e) Convey the object code using peer-to-peer transmission, provided 289 | you inform other peers where the object code and Corresponding 290 | Source of the work are being offered to the general public at no 291 | charge under subsection 6d. 292 | 293 | A separable portion of the object code, whose source code is excluded 294 | from the Corresponding Source as a System Library, need not be 295 | included in conveying the object code work. 296 | 297 | A "User Product" is either (1) a "consumer product", which means any 298 | tangible personal property which is normally used for personal, family, 299 | or household purposes, or (2) anything designed or sold for incorporation 300 | into a dwelling. In determining whether a product is a consumer product, 301 | doubtful cases shall be resolved in favor of coverage. For a particular 302 | product received by a particular user, "normally used" refers to a 303 | typical or common use of that class of product, regardless of the status 304 | of the particular user or of the way in which the particular user 305 | actually uses, or expects or is expected to use, the product. A product 306 | is a consumer product regardless of whether the product has substantial 307 | commercial, industrial or non-consumer uses, unless such uses represent 308 | the only significant mode of use of the product. 309 | 310 | "Installation Information" for a User Product means any methods, 311 | procedures, authorization keys, or other information required to install 312 | and execute modified versions of a covered work in that User Product from 313 | a modified version of its Corresponding Source. The information must 314 | suffice to ensure that the continued functioning of the modified object 315 | code is in no case prevented or interfered with solely because 316 | modification has been made. 317 | 318 | If you convey an object code work under this section in, or with, or 319 | specifically for use in, a User Product, and the conveying occurs as 320 | part of a transaction in which the right of possession and use of the 321 | User Product is transferred to the recipient in perpetuity or for a 322 | fixed term (regardless of how the transaction is characterized), the 323 | Corresponding Source conveyed under this section must be accompanied 324 | by the Installation Information. But this requirement does not apply 325 | if neither you nor any third party retains the ability to install 326 | modified object code on the User Product (for example, the work has 327 | been installed in ROM). 328 | 329 | The requirement to provide Installation Information does not include a 330 | requirement to continue to provide support service, warranty, or updates 331 | for a work that has been modified or installed by the recipient, or for 332 | the User Product in which it has been modified or installed. Access to a 333 | network may be denied when the modification itself materially and 334 | adversely affects the operation of the network or violates the rules and 335 | protocols for communication across the network. 336 | 337 | Corresponding Source conveyed, and Installation Information provided, 338 | in accord with this section must be in a format that is publicly 339 | documented (and with an implementation available to the public in 340 | source code form), and must require no special password or key for 341 | unpacking, reading or copying. 342 | 343 | 7. Additional Terms. 344 | 345 | "Additional permissions" are terms that supplement the terms of this 346 | License by making exceptions from one or more of its conditions. 347 | Additional permissions that are applicable to the entire Program shall 348 | be treated as though they were included in this License, to the extent 349 | that they are valid under applicable law. If additional permissions 350 | apply only to part of the Program, that part may be used separately 351 | under those permissions, but the entire Program remains governed by 352 | this License without regard to the additional permissions. 353 | 354 | When you convey a copy of a covered work, you may at your option 355 | remove any additional permissions from that copy, or from any part of 356 | it. (Additional permissions may be written to require their own 357 | removal in certain cases when you modify the work.) You may place 358 | additional permissions on material, added by you to a covered work, 359 | for which you have or can give appropriate copyright permission. 360 | 361 | Notwithstanding any other provision of this License, for material you 362 | add to a covered work, you may (if authorized by the copyright holders of 363 | that material) supplement the terms of this License with terms: 364 | 365 | a) Disclaiming warranty or limiting liability differently from the 366 | terms of sections 15 and 16 of this License; or 367 | 368 | b) Requiring preservation of specified reasonable legal notices or 369 | author attributions in that material or in the Appropriate Legal 370 | Notices displayed by works containing it; or 371 | 372 | c) Prohibiting misrepresentation of the origin of that material, or 373 | requiring that modified versions of such material be marked in 374 | reasonable ways as different from the original version; or 375 | 376 | d) Limiting the use for publicity purposes of names of licensors or 377 | authors of the material; or 378 | 379 | e) Declining to grant rights under trademark law for use of some 380 | trade names, trademarks, or service marks; or 381 | 382 | f) Requiring indemnification of licensors and authors of that 383 | material by anyone who conveys the material (or modified versions of 384 | it) with contractual assumptions of liability to the recipient, for 385 | any liability that these contractual assumptions directly impose on 386 | those licensors and authors. 387 | 388 | All other non-permissive additional terms are considered "further 389 | restrictions" within the meaning of section 10. If the Program as you 390 | received it, or any part of it, contains a notice stating that it is 391 | governed by this License along with a term that is a further 392 | restriction, you may remove that term. If a license document contains 393 | a further restriction but permits relicensing or conveying under this 394 | License, you may add to a covered work material governed by the terms 395 | of that license document, provided that the further restriction does 396 | not survive such relicensing or conveying. 397 | 398 | If you add terms to a covered work in accord with this section, you 399 | must place, in the relevant source files, a statement of the 400 | additional terms that apply to those files, or a notice indicating 401 | where to find the applicable terms. 402 | 403 | Additional terms, permissive or non-permissive, may be stated in the 404 | form of a separately written license, or stated as exceptions; 405 | the above requirements apply either way. 406 | 407 | 8. Termination. 408 | 409 | You may not propagate or modify a covered work except as expressly 410 | provided under this License. Any attempt otherwise to propagate or 411 | modify it is void, and will automatically terminate your rights under 412 | this License (including any patent licenses granted under the third 413 | paragraph of section 11). 414 | 415 | However, if you cease all violation of this License, then your 416 | license from a particular copyright holder is reinstated (a) 417 | provisionally, unless and until the copyright holder explicitly and 418 | finally terminates your license, and (b) permanently, if the copyright 419 | holder fails to notify you of the violation by some reasonable means 420 | prior to 60 days after the cessation. 421 | 422 | Moreover, your license from a particular copyright holder is 423 | reinstated permanently if the copyright holder notifies you of the 424 | violation by some reasonable means, this is the first time you have 425 | received notice of violation of this License (for any work) from that 426 | copyright holder, and you cure the violation prior to 30 days after 427 | your receipt of the notice. 428 | 429 | Termination of your rights under this section does not terminate the 430 | licenses of parties who have received copies or rights from you under 431 | this License. If your rights have been terminated and not permanently 432 | reinstated, you do not qualify to receive new licenses for the same 433 | material under section 10. 434 | 435 | 9. Acceptance Not Required for Having Copies. 436 | 437 | You are not required to accept this License in order to receive or 438 | run a copy of the Program. Ancillary propagation of a covered work 439 | occurring solely as a consequence of using peer-to-peer transmission 440 | to receive a copy likewise does not require acceptance. However, 441 | nothing other than this License grants you permission to propagate or 442 | modify any covered work. These actions infringe copyright if you do 443 | not accept this License. Therefore, by modifying or propagating a 444 | covered work, you indicate your acceptance of this License to do so. 445 | 446 | 10. Automatic Licensing of Downstream Recipients. 447 | 448 | Each time you convey a covered work, the recipient automatically 449 | receives a license from the original licensors, to run, modify and 450 | propagate that work, subject to this License. You are not responsible 451 | for enforcing compliance by third parties with this License. 452 | 453 | An "entity transaction" is a transaction transferring control of an 454 | organization, or substantially all assets of one, or subdividing an 455 | organization, or merging organizations. If propagation of a covered 456 | work results from an entity transaction, each party to that 457 | transaction who receives a copy of the work also receives whatever 458 | licenses to the work the party's predecessor in interest had or could 459 | give under the previous paragraph, plus a right to possession of the 460 | Corresponding Source of the work from the predecessor in interest, if 461 | the predecessor has it or can get it with reasonable efforts. 462 | 463 | You may not impose any further restrictions on the exercise of the 464 | rights granted or affirmed under this License. For example, you may 465 | not impose a license fee, royalty, or other charge for exercise of 466 | rights granted under this License, and you may not initiate litigation 467 | (including a cross-claim or counterclaim in a lawsuit) alleging that 468 | any patent claim is infringed by making, using, selling, offering for 469 | sale, or importing the Program or any portion of it. 470 | 471 | 11. Patents. 472 | 473 | A "contributor" is a copyright holder who authorizes use under this 474 | License of the Program or a work on which the Program is based. The 475 | work thus licensed is called the contributor's "contributor version". 476 | 477 | A contributor's "essential patent claims" are all patent claims 478 | owned or controlled by the contributor, whether already acquired or 479 | hereafter acquired, that would be infringed by some manner, permitted 480 | by this License, of making, using, or selling its contributor version, 481 | but do not include claims that would be infringed only as a 482 | consequence of further modification of the contributor version. For 483 | purposes of this definition, "control" includes the right to grant 484 | patent sublicenses in a manner consistent with the requirements of 485 | this License. 486 | 487 | Each contributor grants you a non-exclusive, worldwide, royalty-free 488 | patent license under the contributor's essential patent claims, to 489 | make, use, sell, offer for sale, import and otherwise run, modify and 490 | propagate the contents of its contributor version. 491 | 492 | In the following three paragraphs, a "patent license" is any express 493 | agreement or commitment, however denominated, not to enforce a patent 494 | (such as an express permission to practice a patent or covenant not to 495 | sue for patent infringement). To "grant" such a patent license to a 496 | party means to make such an agreement or commitment not to enforce a 497 | patent against the party. 498 | 499 | If you convey a covered work, knowingly relying on a patent license, 500 | and the Corresponding Source of the work is not available for anyone 501 | to copy, free of charge and under the terms of this License, through a 502 | publicly available network server or other readily accessible means, 503 | then you must either (1) cause the Corresponding Source to be so 504 | available, or (2) arrange to deprive yourself of the benefit of the 505 | patent license for this particular work, or (3) arrange, in a manner 506 | consistent with the requirements of this License, to extend the patent 507 | license to downstream recipients. "Knowingly relying" means you have 508 | actual knowledge that, but for the patent license, your conveying the 509 | covered work in a country, or your recipient's use of the covered work 510 | in a country, would infringe one or more identifiable patents in that 511 | country that you have reason to believe are valid. 512 | 513 | If, pursuant to or in connection with a single transaction or 514 | arrangement, you convey, or propagate by procuring conveyance of, a 515 | covered work, and grant a patent license to some of the parties 516 | receiving the covered work authorizing them to use, propagate, modify 517 | or convey a specific copy of the covered work, then the patent license 518 | you grant is automatically extended to all recipients of the covered 519 | work and works based on it. 520 | 521 | A patent license is "discriminatory" if it does not include within 522 | the scope of its coverage, prohibits the exercise of, or is 523 | conditioned on the non-exercise of one or more of the rights that are 524 | specifically granted under this License. You may not convey a covered 525 | work if you are a party to an arrangement with a third party that is 526 | in the business of distributing software, under which you make payment 527 | to the third party based on the extent of your activity of conveying 528 | the work, and under which the third party grants, to any of the 529 | parties who would receive the covered work from you, a discriminatory 530 | patent license (a) in connection with copies of the covered work 531 | conveyed by you (or copies made from those copies), or (b) primarily 532 | for and in connection with specific products or compilations that 533 | contain the covered work, unless you entered into that arrangement, 534 | or that patent license was granted, prior to 28 March 2007. 535 | 536 | Nothing in this License shall be construed as excluding or limiting 537 | any implied license or other defenses to infringement that may 538 | otherwise be available to you under applicable patent law. 539 | 540 | 12. No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | 635 | Copyright (C) 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | Copyright (C) 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | --------------------------------------------------------------------------------