3 | 4 | Complete DSA Preparation Course 5 |
3 | 
74 |
75 |
76 |
77 | _A little Contribution :moneybag:Makes You Happy :heart: (And me Also :blush:)_
78 | 
80 |
81 |
82 |
83 | ``` JavaScript
84 | dsa-course@upi
85 | ```
86 |
87 |
88 |
89 |
90 | > "For coding interview preparation, LeetCode & GeeksforGeeks is one of the best online resource providing a rich library of more than 500+ real coding interview questions for you "
91 |
92 | ## Table of Contents
93 |
94 | - [Time Complexity](#Time-complexity)
95 | - [Mathematics](#mathematics)
96 | - [Bits Manipulation](#Bits-Manipulation)
97 | - [Recursion](#Recursion)
98 | - [Arrays](#Arrays)
99 | - [Searching](#Searching)
100 | - [Sorting](#Sorting)
101 | - [Matrix](#matrix)
102 | - [Hashing](#Hashing)
103 | - [String](#String)
104 | - [Linked List](#Linked-List)
105 | - [Stack](#Stack)
106 | - [Queue](#Queue)
107 | - [Tree](#Tree)
108 | - [Binary Search Tree](#Binary-Search-Tree)
109 | - [Heap](#Heap)
110 | - [Graph](#Graph)
111 | - [Greedy](#Greedy)
112 | - [Backtracking](#Backtracking)
113 | - [Dynamic Programming](#Dynamic-Programming)
114 | - [Trie](#Trie)
115 |
116 |
117 | :green_square:
118 | :orange_square:
119 | :red_square:
120 |
121 |
122 | ## Mathematics
123 |
124 | | # | Title | Code | Document | Video | Difficulty | Tag
125 | |-----|----------------|----------|---------------|---------|-------------|--------
126 | |1|Absolute value||[Theory](https://www.geeksforgeeks.org/program-to-find-absolute-value-of-a-given-number/)||:green_square: Easy| abs() |
127 | |2| Celsius To Fahrenheit ||[Theory](https://www.geeksforgeeks.org/program-celsius-fahrenheit-conversion/)||:green_square: Easy| Math |
128 | |3| Roots of Quadratic equation||[Theory](https://www.geeksforgeeks.org/program-to-find-the-roots-of-quadratic-equation/)||:green_square: Easy| Math |
129 | |4| [Factorial Of Number](https://practice.geeksforgeeks.org/problems/factorial5739/1)||||:green_square: Easy| Math |
130 | |5| [Count digits in a factorial ](https://practice.geeksforgeeks.org/problems/count-digits-in-a-factorial3957/1)||||:green_square: Easy| Factorial, Math |
131 | |6| [Series GP](https://practice.geeksforgeeks.org/problems/series-gp4646/1)||||:green_square: Easy| Basic Math |
132 | |7| [Prime Number](https://practice.geeksforgeeks.org/problems/prime-number2314/1)||||:green_square: Easy| Basic Math |
133 | |8| Exactly 3 Divisors ||[Theory](https://www.geeksforgeeks.org/numbers-exactly-3-divisors/)||:green_square: Easy| Basic Math |
134 | |9| Addition Under Modulo||[Theory](https://www.geeksforgeeks.org/sum-of-two-numbers-modulo-m/)||:green_square: Easy| Modulo |
135 | |10| Multiplication Under Modulo||[Theory](https://www.geeksforgeeks.org/multiply-large-integers-under-large-modulo/)||:green_square: Easy| Modulo |
136 | |11| [Modular Multiplicative Inverse](https://practice.geeksforgeeks.org/problems/modular-multiplicative-inverse-1587115620/1)||||:green_square: Easy| Modulo |
137 | |12| [Trailing zeroes in factorial](https://practice.geeksforgeeks.org/problems/trailing-zeroes-in-factorial5134/1)||||:orange_square: Medium| Logic |
138 | |13| [Prime Factors ](https://practice.geeksforgeeks.org/problems/prime-factors5052/1)||||:orange_square: Medium| Prime |
139 |
140 | ## Bits Manipulation
141 |
142 | | # | Title | Code | Document | Video | Difficulty | Tag
143 | |-----|----------------|----------|---------------|---------|-------------|--------
144 | |1| [Find first set bit](https://practice.geeksforgeeks.org/problems/find-first-set-bit-1587115620/1)| | | |:green_square: Easy| Bits, Modulo |
145 | |2| [Rightmost different bit ](https://practice.geeksforgeeks.org/problems/rightmost-different-bit-1587115621/1)| | | |:green_square: Easy| XOR, Modulo |
146 | |3| [Check whether K-th bit is set or not ](https://practice.geeksforgeeks.org/problems/check-whether-k-th-bit-is-set-or-not-1587115620/1)| | | |:green_square: Easy| XOR, Modulo |
147 | |4| [Count total set bits ](https://practice.geeksforgeeks.org/problems/count-total-set-bits-1587115620/1)| | | |:orange_square: Medium| RIght shift |
148 | |5| [Bit Difference ](https://practice.geeksforgeeks.org/problems/bit-difference-1587115620/1)| | | |:green_square: Easy| Bits |
149 | |6| [Number is sparse or not ](https://practice.geeksforgeeks.org/problems/number-is-sparse-or-not-1587115620/1)| | | |:green_square: Easy| Bits |
150 | |7| [Longest Consecutive 1's ](https://practice.geeksforgeeks.org/problems/longest-consecutive-1s-1587115620/1)| | | |:green_square: Easy| Bits |
151 | |8| [ Gray Code ](https://practice.geeksforgeeks.org/problems/gray-code4907/1)| | | |:green_square: Easy| Xor, Right Shift |
152 | |9| [Gray to Binary equivalent ](https://practice.geeksforgeeks.org/problems/gray-to-binary-equivalent-1587115620/1)| | | |:green_square: Easy| Xor, Right Shift |
153 | |10| [Power of 2](https://practice.geeksforgeeks.org/problems/power-of-2-1587115620/1)| | | |:green_square: Easy| AND |
154 | |11| [Swap all odd and even bits](https://practice.geeksforgeeks.org/problems/swap-all-odd-and-even-bits-1587115621/1)| | | |:green_square: Easy| OR |
155 | |12| [Maximum AND Value ](https://practice.geeksforgeeks.org/problems/maximum-and-value-1587115620/1)| | | |:orange_square: Medium| AND |
156 |
157 |
158 |
159 | ## Recursion
160 |
161 | | # | Title | Code | Document | Video | Difficulty | Tag
162 | |-----|----------------|----------|---------------|---------|-------------|--------
163 | |1| [Print 1 to n without using loops](https://practice.geeksforgeeks.org/problems/print-1-to-n-without-using-loops3621/1)| | | |:green_square: Easy| Recursion|
164 | |2| [Sum Of Digits ](https://practice.geeksforgeeks.org/problems/sum-of-digits1742/1)| | | |:green_square: Easy|Recursion|
165 | |3| [Count Total Digits in a Number ](https://practice.geeksforgeeks.org/problems/count-total-digits-in-a-number/1)| | | |:green_square: Easy|Recursion|
166 | |4| [Digital Root ](https://practice.geeksforgeeks.org/problems/digital-root/1/)| | | |:orange_square: Medium|Recursion|
167 | |5| [Fibonacci Using Recursion](https://practice.geeksforgeeks.org/problems/fibonacci-using-recursion/1/)| | | |:green_square: Easy|Recursion|
168 | |6| [Tower Of Hanoi](https://practice.geeksforgeeks.org/problems/tower-of-hanoi-1587115621/1)| | | |:orange_square: Medium|Recursion|
169 | |7| [Josephus problem](https://practice.geeksforgeeks.org/problems/josephus-problem/1)| | | |:orange_square: Medium|Recursion|
170 |
171 |
172 | ## Arrays
173 |
174 | | # | Title | Code | Document | Video | Difficulty | Tag
175 | |-----|----------------|----------|---------------|---------|-------------|--------
176 | |1| | | | | | |
177 |
178 |
179 |
180 | ## Searching
181 |
182 | | # | Title | Code | Document | Video | Difficulty | Tag
183 | |-----|----------------|----------|---------------|---------|-------------|--------
184 | |1| | | | | | |
185 |
186 |
187 |
188 |
189 | ## Sorting
190 |
191 | | # | Title | Code | Document | Video | Difficulty | Tag
192 | |-----|----------------|----------|---------------|---------|-------------|--------
193 | |1| | | | | | |
194 |
195 |
196 |
197 |
198 | ## Matrix
199 |
200 | | # | Title | Code | Document | Video | Difficulty | Tag
201 | |-----|----------------|----------|---------------|---------|-------------|--------
202 | |1|[What is Multidimensional Arrays c++](https://www.geeksforgeeks.org/multidimensional-arrays-c-cpp/)||[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/multi%20dimension%20array.pdf)|[Video](https://youtu.be/TfE2c7SXaUo)|:green_square: Easy| Matrix, Array |
203 | |2|[Sum of upper and lower triangles ](https://practice.geeksforgeeks.org/problems/sum-of-upper-and-lower-triangles-1587115621/1)||[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Sum%20of%20upper%20and%20lower%20triangles.pdf)|[Solution](https://youtu.be/YuqtMC6Nvg8)|:green_square: Easy| Matrix, Array|
204 | |3|[Transpose of Matrix ](https://practice.geeksforgeeks.org/problems/transpose-of-matrix-1587115621/1)||[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Transpose%20of%20Matrix.pdf)|[Solution](https://youtu.be/n3-XWx-Inns)|:green_square: Easy| Matrix, Array|
205 | |4|[Rotate by 90 degree ](https://practice.geeksforgeeks.org/problems/rotate-by-90-degree-1587115621/1)||[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Rotate%20by%2090%20degree.pdf)|[Solution](https://youtu.be/yIUryrv2I7I)|:green_square: Easy| Matrix, Array|
206 | |5|[Multiply the matrices ](https://practice.geeksforgeeks.org/problems/multiply-the-matrices-1587115620/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Multiply%20two%20matrices.cpp)|[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Multiply%20two%20matrices.pdf)|[Solution](https://youtu.be/DvG9SF2VXL4)|:green_square: Easy| Matrix, Array|
207 | |6|[ Spirally traversing a matrix ](https://practice.geeksforgeeks.org/problems/spirally-traversing-a-matrix-1587115621/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Spirally%20traversing%20a%20matrix.cpp)|[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Spirally%20traversing%20a%20matrix%20.pdf)|[Solution](https://youtu.be/4mSTiSBk_iY)|:orange_square: Medium| Matrix, Array|
208 | |7|[ Interchanging the rows of a Matrix ](https://practice.geeksforgeeks.org/problems/reversing-the-rows-of-a-matrix-1587115621/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Interchanging%20the%20rows%20of%20a%20Matrix.cpp)|[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Interchanging%20The%20Rows%20of%20a%20Matrix.pdf)|[Solution](https://youtu.be/72UDspLEZAg)|:green_square: Easy| Matrix, Array|
209 | |8|[ Matrix Interchange ](https://practice.geeksforgeeks.org/problems/matrix-interchange/1)||| Practice |:green_square: Easy| Matrix, Array|
210 | |9|[ Search in a row-column sorted Matrix ](https://practice.geeksforgeeks.org/problems/search-in-a-matrix-1587115621/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Search%20in%20a%20row-column%20sorted%20Matrix.cpp)|[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Search%20in%20a%20row-column%20sorted%20Matrix.pdf)|[Solution](https://youtu.be/Gy0WeuIuTg4)|:orange_square: Medium| Matrix, Array|
211 | |10|[ Boolean Matrix ](https://practice.geeksforgeeks.org/problems/boolean-matrix-problem-1587115620/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Boolean%20Matrix.cpp)|[Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Boolean%20Matrix.pdf)|[Solution](https://youtu.be/TBTNZXzwpP8)|:orange_square: Medium| Matrix, Array|
212 |
213 |
214 |
215 | ## Hashing
216 |
217 | | # | Title | Code | Document | Video | Difficulty | Tag
218 | |-----|----------------|----------|---------------|---------|-------------|--------
219 | |1|What is Hashing Data structure|| [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Hashing%20in%20Data%20Structure.pdf)|[Theory](https://youtu.be/AV36hu5TFRQ)|:green_square: Easy|Hashing|
220 | |2|Code of Hashing in c++| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/code%20of%20Hashing%20in%20C++.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/code%20of%20Hashing%20in%20C%2B%2B.pdf)|[Solution](https://youtu.be/G87TuBjByts)|:green_square: Easy|Hashing|
221 | |3|Direct Access Table| | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/what%20is%20hashing%20data%20structure%20and%20direct%20access%20table.pdf)|[Theory](https://youtu.be/6qjOspk0Yg0)|:green_square: Easy|Hash|
222 | |4|What is Hash Function and collision| | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/collision%20in%20hashing%20data%20structure.pdf)|[Theory](https://youtu.be/oLR9Zf8JSUI)|:green_square: Easy|Hash|
223 | |5|What is chaining in collision handling| | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/what%20is%20hashing%20data%20structure%20and%20direct%20access%20table.pdf)|[Theory](https://youtu.be/ER03smJIVFE)|:green_square: Easy|Hashing|
224 | |6|What is unordered_set| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/unordered_set.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/unordered_set.pdf)|[Theory](https://youtu.be/EMvLygYr6Gg)|:green_square: Easy|Hash|
225 | |7|What is unordered_map| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/unordered_map.cpp) | [GFG](https://www.geeksforgeeks.org/unordered_map-in-cpp-stl/)|[Theory](https://youtu.be/Uv0kd7mM0ts)|:green_square: Easy|Hash|
226 | |8|[Non Repeating Element](https://practice.geeksforgeeks.org/problems/non-repeating-element3958/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Non-Repeating%20Element.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Non-Repeating%20Element.pdf)|[Solution](https://youtu.be/KpjXziZMHwI)|:green_square: Easy|Hashing|
227 | |9|[First Repeating Element](https://practice.geeksforgeeks.org/problems/first-repeating-element4018/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/First%20Repeating%20Element.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/First%20Repeating%20Element.pdf)|[Solution](https://youtu.be/n5-uvGlhcCI)|:green_square: Easy|Hashing|
228 | |10|[Union of two arrays ](https://practice.geeksforgeeks.org/problems/union-of-two-arrays3538/1)| | | Practice |:green_square: Easy|Hashing|
229 | |11|[Intersection of Two Arrays](https://practice.geeksforgeeks.org/problems/intersection-of-two-arrays2404/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Intersection%20of%20two%20arrays.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Intersection%20of%20two%20arrays.pdf)|[Solution](https://youtu.be/zgLtdM8-6CE)|:green_square: Easy|unordered_set|
230 | |12|[Key Pair](https://practice.geeksforgeeks.org/problems/key-pair5616/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Key%20Pair.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Key%20Pair.pdf)|[Solution](https://youtu.be/7xx1YcXXEYU)|:green_square: Easy|unordered_map|
231 | |13|[Subarray with sum 0](https://practice.geeksforgeeks.org/problems/subarray-with-0-sum-1587115621/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Subarray%20with%200%20sum.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Subarray%20with%200%20sum.pdf)|[Solution](https://youtu.be/8inhayLCCHs)|:orange_square: Medium |unordered_set|
232 | |14|[Winner of an election ](https://practice.geeksforgeeks.org/problems/winner-of-an-election-where-votes-are-represented-as-candidate-names-1587115621/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Winner%20of%20an%20election.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Winner%20of%20an%20election%20.pdf)|[Solution](https://youtu.be/GySYmmehLM0)|:green_square: Easy |unordered_map |
233 | |15|[Pairs with Positive Negative values](https://practice.geeksforgeeks.org/problems/pairs-with-positive-negative-values3719/1)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Pairs%20with%20Positive%20Negative%20values.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Pairs%20with%20Positive%20Negative%20values%20.pdf)|[Solution](https://youtu.be/hCGUty76A6M)|:green_square: Easy |map, Vector |
234 | |16|[Print Anagrams Together ](https://practice.geeksforgeeks.org/problems/print-anagrams-together/1) / [Group Anagrams](https://leetcode.com/problems/group-anagrams/)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Group%20Anagrams.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Group%20Anagrams.pdf) |[Solution](https://youtu.be/zX9k1XvVUXI) |:orange_square: Medium |unordered_map, string |
235 | |17|[Relative Sort Array](https://leetcode.com/problems/relative-sort-array/) / [Sort an array according to the other ](https://practice.geeksforgeeks.org/problems/relative-sorting4323/1) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Relative%20Sort%20Array.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Relative%20Sort%20Array.pdf)|[Solution](https://youtu.be/bNuMPAuQN4g)|:orange_square: Medium |Map|
236 | |18|[Custom Sort String ](https://leetcode.com/problems/custom-sort-string/)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Custom%20Sort%20String.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Custom%20Sort%20String.pdf) | [Solution](https://youtu.be/z4KYZGv7L-I) |:orange_square: Medium | map |
237 | |19|[Sort Array by Increasing Frequency ](https://leetcode.com/problems/sort-array-by-increasing-frequency/)| [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Sort%20Array%20by%20Increasing%20Frequency.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Hashing/Sort%20Array%20by%20Increasing%20Frequency.pdf) | [Solution](https://youtu.be/PjKjbpI2Z3s) |:green_square: Easy | map, Lambda |
238 | |20|[Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/)| | | Practice |:orange_square: Medium | map |
239 |
240 |
241 |
242 | ## String
243 |
244 | | # | Title | Code | Document | Video | Difficulty | Tag
245 | |-----|----------------|----------|---------------|---------|-------------|--------
246 | |1| Naive Pattern Search | | | [Important](https://youtu.be/_ZWnkyae2gA) | :green_square: Easy | Pattern |
247 | |2| [Implement strStr()](https://leetcode.com/problems/implement-strstr/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Naive%20Pattern%20Search.cpp) | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Naive%20Pattern%20Search%20:%20Implement%20strStr()%20.pdf) | | :green_square: Easy | Pattern |
248 | |3| [Binary String ](https://practice.geeksforgeeks.org/problems/binary-string-1587115620/1) | | | | :green_square: Easy | string |
249 | |4| [Anagram ](https://practice.geeksforgeeks.org/problems/anagram-1587115620/1) | | | | :green_square: Easy | string |
250 | |5| [Check if string is rotated by two places ](https://practice.geeksforgeeks.org/problems/check-if-string-is-rotated-by-two-places-1587115620/1) | | | | :green_square: Easy | string |
251 | |6| [Check if strings are rotations of each other or not ](https://practice.geeksforgeeks.org/problems/check-if-strings-are-rotations-of-each-other-or-not-1587115620/1) | | | | :green_square: Easy | string |
252 | |7| [Isomorphic Strings ](https://practice.geeksforgeeks.org/problems/isomorphic-strings-1587115620/1) | | | | :green_square: Easy | string |
253 | |8| [Check if a string is Isogram or not ](https://practice.geeksforgeeks.org/problems/check-if-a-string-is-isogram-or-not-1587115620/1) | | | | :green_square: Easy | string |
254 | |9| [Keypad typing ](https://practice.geeksforgeeks.org/problems/keypad-typing0119/1) | | | | :green_square: Easy | string |
255 | |10| [Repeated Character ](https://practice.geeksforgeeks.org/problems/repeated-character2058/1) | | | | :green_square: Easy | string |
256 | |11| [ Non Repeating Character ](https://practice.geeksforgeeks.org/problems/non-repeating-character-1587115620/1) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Non%20Repeating%20Character.cpp) | | [solution](https://youtu.be/MN37co8M37g) | :orange_square: Medium | string |
257 | |12| [ Maximum Occuring Character ](https://practice.geeksforgeeks.org/problems/maximum-occuring-character-1587115620/1) | | | | :green_square: Easy | string |
258 | |13| [ Remove common characters and concatenate ](https://practice.geeksforgeeks.org/problems/remove-common-characters-and-concatenate-1587115621/1) | | | | :green_square: Easy | string |
259 | |14| [ Reverse words in a given string ](https://practice.geeksforgeeks.org/problems/reverse-words-in-a-given-string5459/1) | | | | :green_square: Easy | string |
260 | |15| [ Sum of numbers in string ](https://practice.geeksforgeeks.org/problems/sum-of-numbers-in-string-1587115621/1) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/sum%20of%20numbers%20in%20string.cpp)| [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/sum%20of%20numbers%20in%20string.pdf) | [solution](https://youtu.be/XdbGdoTf3Fs) | :orange_square: Medium | string |
261 | |16| [ Pangram Checking ](https://practice.geeksforgeeks.org/problems/pangram-checking-1587115620/1) | | | | :green_square: Easy | string |
262 | |17| [ Minimum indexed character ](https://practice.geeksforgeeks.org/problems/minimum-indexed-character-1587115620/1) | | | | :green_square: Easy | string |
263 | |18| [ Smallest window in a string containing all the characters of another string ](https://practice.geeksforgeeks.org/problems/smallest-window-in-a-string-containing-all-the-characters-of-another-string-1587115621/1) | | | | :orange_square: Medium | string |
264 | |19| [ Nth number made of prime digits ](https://practice.geeksforgeeks.org/problems/nth-number-made-of-prime-digits4319/1) | | | | :green_square: Easy | Prime, string |
265 |
266 |
267 |
268 |
269 | ## Linked List
270 |
271 | | # | Title | Code | Document | Video | Difficulty | Tag
272 | |-----|----------------|----------|---------------|---------|-------------|--------
273 | |1| Introduction to Linked list Playlist c++ |||[Theory](https://youtu.be/rrPsVNwvfxg)|:green_square: Easy|Linked List|
274 | |2| Data structures Competitive Programming |||[Theory](https://youtu.be/zwjLygQPBb0)|:green_square: Easy|DSA|
275 | |3| Arrays in Data Structures |||[Theory](https://youtu.be/vPfD_50rwog)|:green_square: Easy|Arrays|
276 | |4| Pointers in C++ with code Practice |||[Theory](https://youtu.be/-x0QnooY6O8)|:green_square: Easy|Pointers|
277 | |5| Struct in c++ |||[Theory](https://youtu.be/PLivrxyXTMc)|:green_square: Easy|Struct|
278 |
279 |
280 |
281 |
282 |
283 | ## Stack
284 |
285 | | # | Title | Code | Document | Video | Difficulty | Tag
286 | |-----|----------------|----------|---------------|---------|-------------|--------
287 | |1| What is stack | |[GFG Link](https://www.geeksforgeeks.org/stack-data-structure-introduction-program/)|[Solution](https://youtu.be/cppd9DhKHYc)|:green_square: Easy| Stack, Array|
288 | |2| [Implement stack using array](https://practice.geeksforgeeks.org/problems/implement-stack-using-array/1) | | | |:green_square: Easy| Stack, Array|
289 | |3| [Implement Stack using Linked List ](https://practice.geeksforgeeks.org/problems/implement-stack-using-linked-list/1) | | | |:green_square: Easy| Stack, Linked List|
290 | |4| [Implement Stack using Linked List ](https://practice.geeksforgeeks.org/problems/implement-stack-using-linked-list/1) | | | |:green_square: Easy| Stack, Linked List|
291 | |5| [Remove All Adjacent Duplicates In String](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string/) | | | |:green_square: Easy| Stack, string|
292 | |6| [Remove All Adjacent Duplicates in String II](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii/) | | | |:orange_square: Medium| Stack, string|
293 | |7| [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/) | | | |:green_square: Easy| Stack, string|
294 | |8| [Implement two stacks in an array](https://practice.geeksforgeeks.org/problems/implement-two-stacks-in-an-array/1) | | | |:green_square: Easy| Stack, Array|
295 | |9| [Valid Parentheses](https://leetcode.com/problems/valid-parentheses/) | | | |:green_square: Easy| Stack, string|
296 | |10| [Get min at pop ](https://practice.geeksforgeeks.org/problems/get-min-at-pop/1/) | | | |:green_square: Easy| Stack, Array|
297 | |11| [Min Stack](https://leetcode.com/problems/min-stack/) | | | |:green_square: Easy| Stack, Array|
298 | |12| [Delete middle element of a stack ](https://practice.geeksforgeeks.org/problems/delete-middle-element-of-a-stack/1) | | | |:green_square: Easy| Stack, STL|
299 | |13| [Infix to Postfix](https://practice.geeksforgeeks.org/problems/infix-to-postfix-1587115620/1) | | | |:green_square: Easy| Stack |
300 | |14| [Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/) | | | |:orange_square: Medium| Stack, Evaluation of Postfix Expression|
301 | |15| [Online Stock Span](https://leetcode.com/problems/online-stock-span/) | | | |:orange_square: Medium| Stack, Stock span problem |
302 | |16| [Next Greater Element II](https://leetcode.com/problems/next-greater-element-ii/) | | | |:orange_square: Medium| Stack, Array |
303 | |17| [Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/) | | | |:red_square: Hard| Stack, Array |
304 | |18| [The Celebrity Problem ](https://practice.geeksforgeeks.org/problems/the-celebrity-problem/1/) | | | |:orange_square: Medium| Stack, Array |
305 |
306 |
307 | ## Queue
308 |
309 | | # | Title | Code | Document | Video | Difficulty | Tag
310 | |-----|----------------|----------|---------------|---------|-------------|--------
311 | |1| What is Queue | |[GFG Link](https://www.geeksforgeeks.org/queue-set-1introduction-and-array-implementation/)|[Solution](https://youtu.be/f-7SBV09Ots)|:green_square: Easy| Queue, STL|
312 | |2| [Implement Queue using array ](https://practice.geeksforgeeks.org/problems/implement-queue-using-array/1) | | | |:green_square: Easy| Queue, Array|
313 | |3| [Implement Queue using Linked List](https://practice.geeksforgeeks.org/problems/implement-queue-using-linked-list/1) | | [Scaler Topics Link](https://www.scaler.com/topics/c/implementation-of-queue-using-linked-list/) | |:green_square: Easy| Queue, Linked List|
314 | |4| [Queue Reversal](https://practice.geeksforgeeks.org/problems/queue-reversal/1/) | | | |:green_square: Easy| Queue, Stack|
315 | |5| [Queue using two Stacks](https://practice.geeksforgeeks.org/problems/queue-using-two-stacks/1) | | | |:green_square: Easy| Queue, Stack|
316 | |6| [Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks/) | | | |:green_square: Easy| Stack, Queue|
317 | |7| [Stack using two queues](https://practice.geeksforgeeks.org/problems/stack-using-two-queues/1) | | | |:green_square: Easy| Stack, Queue|
318 | |8| [Generate Binary Numbers](https://practice.geeksforgeeks.org/problems/generate-binary-numbers-1587115620/1) | | | |:green_square: Easy| Queue |
319 | |9| [Reverse First K elements of Queue](https://practice.geeksforgeeks.org/problems/reverse-first-k-elements-of-queue/1) | | | |:green_square: Easy| Queue, Stack|
320 | |10| [Circular tour](https://practice.geeksforgeeks.org/problems/circular-tour-1587115620/1) | | | |:orange_square: Medium| Queue, Sliding window|
321 |
322 |
323 |
324 |
325 | ## Tree
326 |
327 |
328 | | # | Question | Code | Document | Video | Difficulty | Tag
329 | |-----|----------------|----------|---------------|---------|-------------|--------
330 | |1| What is Tree | | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Tree%20data_structure.pdf) | [Solution1](https://youtu.be/nbgtyBKn2tI), [solution2](https://youtu.be/9Z87SnIua8I) | :green_square: Easy | Tree, Theory |
331 | |2| What is Binary tree | | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Binary_tree.pdf) | [solution](https://youtu.be/cS5XtSXm6fw) | :green_square: Easy | Tree, Binary Tree |
332 | |3| How to code binary tree | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Binary_tree.cpp) | | [Solution](https://youtu.be/r7ytFtYaFV0)| :green_square: Easy | Tree, Code |
333 | |4| Properties of Binary tree | | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/properties%20of%20Binary%20tree.pdf) | [solution](https://youtu.be/bu1xCi6izdA)| :green_square: Easy | Tree, Node|
334 | |5| Types of Binary tree | | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Types%20of%20Binary%20Tree.pdf)| [solution](https://youtu.be/NUMEZO-BziM)| :green_square: Easy | Binary Tree|
335 | |6| Tree Traversal | | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Tree%20traversal%20data_structure.pdf) | [solution1](https://youtu.be/oTA58OYsO5A), [solution2](https://youtu.be/XZPCADenpWY)| :green_square: Easy | Traversal, Inorder|
336 | |7| Code of Inorder Traversal | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Code%20of%20Inorder%20Traversal.cpp) | [pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/Code%20of%20Inorder%20Traversal.pdf) | [solution](https://youtu.be/EswF52mFtmo)| :green_square: Easy | Inorder Traversal |
337 | |8| Code of Preorder and Postorder | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Tree/code%20of%20preorer%20and%20Postorder%20traversal.cpp)| | [Solution](https://youtu.be/hgmC_ss13yQ)| :green_square: Easy | Preorder, Postorder |
338 | |9| [Binary Tree Inorder Traversal ](https://leetcode.com/problems/binary-tree-inorder-traversal/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/Binary%20Tree%20Inorder%20Traversal.cpp) | | [Solution](https://youtu.be/pnVw3yo-3Kg) | :green_square: Easy | Recursion, Tree |
339 | |10| [Binary Tree Preorder Traversal ](https://leetcode.com/problems/binary-tree-preorder-traversal/) | | | Practice | :green_square: Easy | Recursion, Tree |
340 | |11| [Binary Tree Postorder Traversal ](https://leetcode.com/problems/binary-tree-postorder-traversal/) | | | Practice | :green_square: Easy | Recursion, Tree |
341 | |12| [Same Tree](https://leetcode.com/problems/same-tree/) |[c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/same%20Tree.cpp) | | [Solution](https://youtu.be/3104dX4_zwI) | :green_square: Easy | Tree Traversal |
342 | |13| [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/Maximum%20Depth%20of%20Binary%20Tree.cpp) | | [Solution](https://youtu.be/u9gLZIlomn4) | :orange_square: Medium | Recursion, Tree |
343 | |14| [Children Sum Parent ](https://practice.geeksforgeeks.org/problems/children-sum-parent/1/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/Children%20Sum%20Parent.cpp) | | [Solution](https://youtu.be/vv2hUDCnKP0) | :green_square: Easy | Recursion, Tree |
344 | |15| [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/Level%20Order%20Traversal.cpp) | | [Solution](https://youtu.be/me7AXvWv4jc) | :orange_square: Medium | Queue, Tree |
345 | |16| [Level order traversal Line by Line](https://practice.geeksforgeeks.org/problems/level-order-traversal-line-by-line/1/) | | | Practice | :green_square: Easy | stack, Tree |
346 | |17| [Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/Binary%20Tree%20Zigzag%20Level%20Order%20Traversal.cpp) | | [Solution](https://youtu.be/pgc-Mo_1E58) | :orange_square: Medium | Queue, Tree |
347 | |18| [Maximum Width of Tree](https://practice.geeksforgeeks.org/problems/maximum-width-of-tree/1) | | | | :green_square: Easy | Tree |
348 | |19| [Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/) | [c++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Tree/Balanced%20Binary%20Tree.cpp) | | [Solution](https://www.youtube.com/watch?v=gkssX4evzkM&t=1s) | :green_square: Easy | Tree |
349 | |20| [Left View of Binary Tree](https://practice.geeksforgeeks.org/problems/left-view-of-binary-tree/1) | | | | :green_square: Easy | Tree |
350 | |21| [Right View of Binary Tree ](https://practice.geeksforgeeks.org/problems/right-view-of-binary-tree/1) | | | | :green_square: Easy | Tree |
351 | |22| [Lowest Common Ancestor in a Binary Tree ](https://practice.geeksforgeeks.org/problems/lowest-common-ancestor-in-a-binary-tree/1/) | | | | :orange_square: Medium | Tree |
352 | |23| [Diameter of Binary Tree](https://practice.geeksforgeeks.org/problems/diameter-of-binary-tree/1/) | | | | :green_square: Easy | Tree |
353 | |24| [Vertical Width of a Binary Tree](https://practice.geeksforgeeks.org/problems/vertical-width-of-a-binary-tree/1/) | | | | :green_square: Easy | Tree |
354 | |25| [Mirror Tree ](https://practice.geeksforgeeks.org/problems/mirror-tree/1/) | | | | :green_square: Easy | Tree |
355 | |26| [Check if subtree ](https://practice.geeksforgeeks.org/problems/check-if-subtree/1/) | | | | :orange_square: Medium | Tree |
356 | |27| [Make Binary Tree From Linked List ](https://practice.geeksforgeeks.org/problems/make-binary-tree/1) | | | | :orange_square: Medium | Tree |
357 |
358 |
359 |
360 | ## Binary Search Tree
361 |
362 | | # | Title | Code | Document | Video | Difficulty | Tag
363 | |-----|----------------|----------|---------------|---------|-------------|--------
364 | |1| [Inorder traversal of a BST ](https://practice.geeksforgeeks.org/problems/inorder-traversal-of-a-bst/1/) | | | | :green_square: Easy | BST, Tree |
365 | |2| [Search in a Binary Search Tree ](https://leetcode.com/problems/search-in-a-binary-search-tree/) | | | | :green_square: Easy | BST, Tree |
366 |
367 |
368 |
369 | ## Heap
370 |
371 | | # | Title | Code | Document | Video | Difficulty | Tag
372 | |-----|----------------|----------|---------------|---------|-------------|--------
373 | |1| [Heap sort](https://practice.geeksforgeeks.org/problems/heap-sort/1) | | | [Solution](https://youtu.be/79KoeErdQtk) | :green_square: Easy | Heap Basic |
374 | |2| [Kth Largest Element in an Array](https://leetcode.com/problems/kth-largest-element-in-an-array/) | | | [Solution](https://youtu.be/g5mmW0GOTx8) | :green_square: Easy | Heap Basic |
375 | |3| [Kth Largest Element in a Stream](https://leetcode.com/problems/kth-largest-element-in-a-stream/) | | | [Solution](https://youtu.be/8HR8Ak5zuus) | :green_square: Easy | Heap Basic |
376 | |4| [Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/) | | | [Solution](https://youtu.be/3YFFqwzxosU) | :green_square: Easy | Heap Basic |
377 | |5| [Minimum Cost of ropes](https://practice.geeksforgeeks.org/problems/minimum-cost-of-ropes-1587115620/1) | | | [Solution](https://youtu.be/mRtq1ucnjJg) | :green_square: Easy | Heap Basic |
378 | |6| [Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements/) | | | [Solution](https://youtu.be/Of4bdCDwcdY) | :orange_square: Medium | Heap Medium |
379 | |7| [Merge k Sorted Arrays](https://practice.geeksforgeeks.org/problems/merge-k-sorted-arrays/1) | | | [Solution](https://youtu.be/l8CuET0jlDU) | :orange_square: Medium | Heap Medium |
380 | |8| [Find median in a stream](https://practice.geeksforgeeks.org/problems/find-median-in-a-stream-1587115620/1) | | | [Solution](https://youtu.be/cjQNm2eS6Lw) | :red_square: Hard | Heap Hard |
381 |
382 |
383 |
384 | ## Graph
385 |
386 | | # | Title | Code | Document | Video | Difficulty | Tag
387 | |-----|----------------|----------|---------------|---------|-------------|--------
388 | |1| Graph Introduction | | | [Solution](https://youtu.be/Y_0-AmbC0Ig) | :green_square: Easy | Graph Theory |
389 | |2| Adjacency Matrix in graph | | | [Solution](https://youtu.be/9MdpJuYliQM) | :green_square: Easy | Graph Basic |
390 | |3| Adjacency List in graph | | | [Solution](https://youtu.be/Ysh31pZqIQs) | :green_square: Easy | Graph |
391 | |4| How to code graph | | | [Solution](https://youtu.be/MjOwemGFoR8) | :green_square: Easy | Graph |
392 | |5| BFS Of Graph | | | [Solution](https://youtu.be/pQTbrRhuWXI) | :green_square: Easy | Graph Theory |
393 | |6| [Find If Path Exists in Graph](https://leetcode.com/problems/find-if-path-exists-in-graph/) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Find%20if%20Path%20Exists%20in%20Graph.cpp) | | [Solution](https://youtu.be/QC4bDHEnmLM) | :green_square: Easy | Graph BFS |
394 | |7| [Find the Town Judge](https://leetcode.com/problems/find-the-town-judge/) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Find%20the%20Town%20Judge.cpp) | | [Solution](https://youtu.be/V_MPL5O-hDw) | :green_square: Easy | Graph BFS |
395 | |8| DFS Of Graph | | | [Solution](https://youtu.be/7jDCxMQW1GA) | :green_square: Easy | Graph Theory |
396 | |9| [Number of Islands](https://leetcode.com/problems/number-of-islands/) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Number%20of%20Islands.cpp) | | [Solution](https://youtu.be/UbzHYtUwKOY) | :orange_square: Medium | Graph DFS |
397 | |10| [Flood Fill](https://leetcode.com/problems/flood-fill/) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Flood%20Fill.cpp) | | [Solution](https://youtu.be/7aikf56h9Gs) | :green_square: Easy | Graph Theory |
398 | |11| Detect cycle in undirected graph | | | [Solution](https://youtu.be/KPLn9DjwpW4) | :green_square: Easy | Graph |
399 | |12| [Topological sort (Kahn's BFS)](https://practice.geeksforgeeks.org/problems/topological-sort/1) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Topological%20sort%20.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Topological%20sort.pdf) | [Solution](https://youtu.be/X7VdEG51__E) | :green_square: Easy | Graph |
400 | |13| [Topological sort using DFS](https://practice.geeksforgeeks.org/problems/topological-sort/1) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Topological%20sort%20using%20dfs.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Topological%20sort%20using%20dfs.pdf) | [Solution](https://youtu.be/tv8yJLKOZ0g) | :orange_square: Medium | Graph DFS |
401 | |14| [Detect Cycle in a Directed Graph](https://practice.geeksforgeeks.org/problems/detect-cycle-in-a-directed-graph/1) | [C++](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Detect%20cycle%20in%20a%20directed%20graph.cpp) | [Pdf](https://github.com/Prince-1501/Hello_world-Competiitve-Programming/blob/master/Leetcode/Graph/Detect%20cycle%20in%20a%20directed%20graph.pdf) | [Solution](https://youtu.be/TL9oORCqHe8) | :orange_square: Medium | Graph GFG |
402 |
403 |
404 |
405 |
406 |
407 |
408 | ## Greedy
409 |
410 | | # | Title | Code | Document | Video | Difficulty | Tag
411 | |-----|----------------|----------|---------------|---------|-------------|--------
412 | |1|
413 |
414 |
415 |
416 | ## Backtracking
417 |
418 | | # | Title | Code | Document | Video | Difficulty | Tag
419 | |-----|----------------|----------|---------------|---------|-------------|--------
420 | |1|
421 |
422 |
423 | ## Dynamic Programming
424 |
425 | | # | Title | Code | Document | Video | Difficulty | Tag
426 | |-----|----------------|----------|---------------|---------|-------------|--------
427 | |1| [Fibonacci Numbers - Top Down DP](https://practice.geeksforgeeks.org/problems/fibonacci-numbers-top-down-dp/1) | | | | :green_square: Easy | Recursion |
428 |
429 |
430 | ## Trie
431 |
432 | | # | Title | Code | Document | Video | Difficulty | Tag
433 | |-----|----------------|----------|---------------|---------|-------------|--------
434 | |1| [Insert and Search](https://practice.geeksforgeeks.org/problems/trie-insert-and-search0651/1) | | | | :orange_square: Medium | Trie |
435 |
436 |
437 | 
450 | 
451 | 
452 |
453 | ***Do star, fork and share the repo to show your support, it would help others too!***