[Manan] ADD:Checking if the entered string is palindrome or not

Author: mananguptamg

PalindromeString.java

@@ -0,0 +1,75 @@
+import java.util.Scanner;
+
+class PalindromeString {
+    // Logic 1: using two-pointers approach
+    public static boolean isPalindromeStringTwoPointer(String s) {
+        int start = 0, end = s.length() - 1;
+        while (start < end) {
+            if (s.charAt(start) != s.charAt(end)) {
+                return false;
+            }
+            start++;
+            end--;
+        }
+        return true;
+    } 
+
+    // Logic 2: Using Recursion approach
+    public static boolean isPalindromeStringRecursive(String s, int start, int end) {
+        if (start >= end) {
+            return true;
+        }
+        if (s.charAt(start) != s.charAt(end)) {
+            return false;
+        }
+        return isPalindromeStringRecursive(s, start + 1, end - 1);
+    }
+
+    // Logic 3: Using character array and reverse comparison approach
+    public static boolean isPalindromeStringCharArray(String s) {
+        char[] originalArray = s.toCharArray();
+        char[] reversedArray = reverseString(s);
+
+        // Compare original and reversed arrays
+        for (int i = 0; i < originalArray.length; i++) {
+            if (originalArray[i] != reversedArray[i]) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    // Method to reverse a string
+    public static char[] reverseString(String s) {
+        char[] reversed = new char[s.length()];
+        for (int i = 0; i < s.length(); i++) {
+            reversed[i] = s.charAt(s.length() - 1 - i);
+        }
+        return reversed;
+    }
+
+    // Main method
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+
+        System.out.print("Enter a string: ");
+        String userInput = input.nextLine();
+
+        // Checking using all three logic methods
+        boolean result1 = isPalindromeStringTwoPointer(userInput);
+        boolean result2 = isPalindromeStringRecursive(userInput, 0, userInput.length() - 1);
+        boolean result3 = isPalindromeStringCharArray(userInput);
+
+        // Display results
+        System.out.println("[Logic 1] Is the string a palindrome? " + result1);
+        System.out.println("[Logic 2] Is the string a palindrome? " + result2);
+        System.out.println("[Logic 3] Is the string a palindrome? " + result3);
+
+        // Compare the results
+        if (result1 == result2 && result2 == result3) {
+            System.out.println("All methods give the same result.");
+        } else {
+            System.out.println("Results are not the same.");
+        }
+    }
+}