Add 5_Longest_Palindromic_Substring.java

Author: Sean Prashad

Dynamic Programming/5_Longest_Palindromic_Substring.java

@@ -0,0 +1,23 @@
+class Solution {
+    public String longestPalindrome(String s) {
+        if (s == null || s.length() == 0) {
+            return s;
+        }
+
+        int start = 0, end = 0, n = s.length();
+        boolean[][] dp = new boolean[n][n];
+
+        for (int i = n - 1; i >= 0; i--) {
+            for (int j = i; j < n; j++) {
+                dp[i][j] = s.charAt(i) == s.charAt(j) && (j - i < 2 || dp[i + 1][j - 1]);
+
+                if (dp[i][j] && j - i > end - start) {
+                    start = i;
+                    end = j;
+                }
+            }
+        }
+
+        return s.substring(start, end + 1);
+    }
+}