├── INTERFACE.java
├── Kadane's Algorithm
├── PALINDROME.java
├── REVERSE_THE_NUMBER.java
└── string methods.java


/INTERFACE.java:
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 1 | interface  Animal{
 2 |     void walk();
 3 | }
 4 | interface dog{
 5 |     void bark();
 6 | }
 7 | class Man implements Animal,dog{
 8 |     public void walk(){
 9 |         System.out.println("ANIMAL CAN WALK");
10 |     }
11 |     public void bark(){
12 |         System.out.println("DOG CAN WALK");
13 |     }
14 | }
15 | 
16 | 
17 | public class interface1{
18 |     public static void main(String args[]){
19 |     Man a1=new Man();
20 |     a1.walk();
21 |     a1.bark();
22 | }
23 | }
24 | 


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/Kadane's Algorithm:
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 1 | class Solution {
 2 |     int maxSubarraySum(int[] arr) {
 3 |         
 4 |         int currentSum = arr[0];
 5 |         int maxSum = arr[0];
 6 |         
 7 |         for(int i = 1; i<arr.length; i++){
 8 | 
 9 |            currentSum = Math.max(arr[i], currentSum + arr[i]);
10 |            
11 |            maxSum = Math.max(maxSum , currentSum);
12 |             
13 |         }
14 |         
15 |         
16 |         return maxSum;
17 |         
18 |         
19 |     }
20 | }
21 | 


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/PALINDROME.java:
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 1 | import java.util.*;
 2 | class Main {
 3 |     public static void main(String[] args) {
 4 |         Scanner sc=new Scanner(System.in);
 5 |         System.out.print("Enter a value to check: ");
 6 |         int a=sc.nextInt();
 7 |         int temp =a;
 8 |         int rev=0;
 9 |         while(temp!=0){
10 |             rev=rev*10+temp%10;
11 |             temp=temp/10;
12 |         }
13 |         if(rev==a){
14 |             System.out.print("PALINDROME Number");
15 |             }
16 |         else{
17 |             System.out.print("NOT PALINDROME");
18 |         }
19 |         
20 |     }
21 | }
22 | 


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/REVERSE_THE_NUMBER.java:
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 1 | import java.util.*;
 2 | class Main {
 3 |     public static void main(String[] args) {
 4 |         Scanner sc=new Scanner(System.in);
 5 |         System.out.print("Enter a value to reverse: ");
 6 |         int a=sc.nextInt();
 7 |         int rev=0;
 8 |         while(a!=0){
 9 |             rev=rev*10+a%10;
10 |             a=a/10;
11 |         }
12 |         System.out.println("REVERSED NUMBER: "+rev);
13 |     }
14 | }
15 | 


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/string methods.java:
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 1 | public class StringMethodsExample {
 2 |     public static void main(String[] args) {
 3 |         // 1. substring(int beginIndex)
 4 |         String str = "Hello, World!";
 5 |         System.out.println("substring(7): " + str.substring(7)); // Output: "World!"
 6 | 
 7 |         // 2. substring(int beginIndex, int endIndex)
 8 |         System.out.println("substring(7, 12): " + str.substring(7, 12)); // Output: "World"
 9 | 
10 |         // 3. isEmpty()
11 |         String emptyStr = "";
12 |         System.out.println("isEmpty(): " + emptyStr.isEmpty()); // Output: true
13 |         System.out.println("isEmpty(): " + str.isEmpty()); // Output: false
14 | 
15 |         // 4. concat(String str)
16 |         String concatStr = str.concat(" Welcome!");
17 |         System.out.println("concat(): " + concatStr); // Output: "Hello, World! Welcome!"
18 | 
19 |         // 5. replace(char old, char new)
20 |         System.out.println("replace('o', 'a'): " + str.replace('o', 'a')); // Output: "Hella, Warld!"
21 | 
22 |         // 6. replace(CharSequence old, CharSequence new)
23 |         System.out.println("replace(\"World\", \"Java\"): " + str.replace("World", "Java")); // Output: "Hello, Java!"
24 | 
25 |         // 7. split(String regex)
26 |         String csv = "apple,banana,grape";
27 |         String[] fruits = csv.split(",");
28 |         System.out.println("split(\",\"): ");
29 |         for (String fruit : fruits) {
30 |             System.out.println(fruit);
31 |         }
32 | 
33 |         // 8. split(String regex, int limit)
34 |         String[] limitedFruits = csv.split(",", 2);
35 |         System.out.println("split(\",\", 2): ");
36 |         for (String fruit : limitedFruits) {
37 |             System.out.println(fruit);
38 |         }
39 | 
40 |         // 9. indexOf(int ch)
41 |         System.out.println("indexOf('o'): " + str.indexOf('o')); // Output: 4
42 | 
43 |         // 10. indexOf(int ch, int fromIndex)
44 |         System.out.println("indexOf('o', 5): " + str.indexOf('o', 5)); // Output: 8
45 | 
46 |         // 11. indexOf(String substring)
47 |         System.out.println("indexOf(\"World\"): " + str.indexOf("World")); // Output: 7
48 | 
49 |         // 12. indexOf(String substring, int fromIndex)
50 |         System.out.println("indexOf(\"o\", 5): " + str.indexOf("o", 5)); // Output: 8
51 | 
52 |         // 13. trim()
53 |         String spacedStr = "   Hello, Java!   ";
54 |         System.out.println("trim(): " + "\"" + spacedStr.trim() + "\""); // Output: "Hello, Java!"
55 | 
56 |         // 14. static String valueOf(int value)
57 |         int number = 123;
58 |         String numberStr = String.valueOf(number);
59 |         System.out.println("valueOf(123): " + numberStr); // Output: "123"
60 | 
61 |         // Using valueOf for other types
62 |         char ch = 'A';
63 |         double pi = 3.14159;
64 |         System.out.println("valueOf('A'): " + String.valueOf(ch)); // Output: "A"
65 |         System.out.println("valueOf(3.14159): " + String.valueOf(pi)); // Output: "3.14159"
66 |         }
67 | }
68 | 


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