Add brute force solution for longest palindromic substring

sayampradhan · web-flow · commit 2f48aef31ad2 · 2026-04-06T22:29:20.000+05:30
diff --git a/phase-3-data-structures/18_palindrome_substring_brute_force.cpp b/phase-3-data-structures/18_palindrome_substring_brute_force.cpp
@@ -0,0 +1,44 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+// Function to check if a string is palindrome
+bool isPalindrome(string s) {
+    int left = 0, right = s.length() - 1;
+    while (left < right) {
+        if (s[left] != s[right])
+            return false;
+        left++;
+        right--;
+    }
+    return true;
+}
+
+// Function to find longest palindromic substring (brute force)
+string longestPalindrome(string str) {
+    int n = str.length();
+    string longest = "";
+
+    for (int i = 0; i < n; i++) {
+        for (int j = i; j < n; j++) {
+            string sub = str.substr(i, j - i + 1);
+
+            if (isPalindrome(sub) && sub.length() > longest.length()) {
+                longest = sub;
+            }
+        }
+    }
+
+    return longest;
+}
+
+int main() {
+    string str;
+    cout << "Enter string: ";
+    cin >> str;
+
+    string result = longestPalindrome(str);
+    cout << "Longest Palindromic Substring: " << result << endl;
+
+    return 0;
+}
