longest palindrome substring

Author: accodes21

longestPalindromeSubstr.cpp

@@ -0,0 +1,29 @@
+class Solution {
+    private:
+    int expandString(const string &s, int left, int right){
+        while(left>=0 && right<s.size() && s[left] == s[right]){
+            left--;
+            right++;
+        }
+        return right - left - 1;
+    }
+
+public:
+    string longestPalindrome(string s) {
+        int n = s.size();
+        int maxlen = 0;
+        int start = 0;
+
+        for(int i = 0; i<n; i++){
+            int l1 = expandString(s,i,i);
+            int l2 = expandString(s,i,i+1);
+            int l = max(l1,l2);
+
+            if(l > maxlen){
+                maxlen = l;
+                start = i - (l-1)/2;
+            }
+        }
+        return s.substr(start, maxlen);
+    }
+};