problem 5

LongestPalindromicSubstring.cpp

@@ -0,0 +1,40 @@
+#include <string>
+
+using namespace std;
+class Solution
+{
+public:
+    string longestPalindrome(string s)
+    {
+        int max{};
+        int index{};
+        for (int i = 0; i < s.length(); i++)
+        {
+            int j = 0;
+            while (i - j >= 0 && i + j < s.length() && s[i - j] == s[i + j])
+            {
+                j++;
+            }
+            if (j * 2 - 1 > max)
+            {
+                max = j * 2 - 1;
+                index = i;
+            }
+            j = 0;
+            while (i - j >= 0 && i + j + 1 < s.length() && s[i - j] == s[i + j + 1])
+            {
+                j++;
+            }
+            if (j * 2 > max)
+            {
+                max = j * 2;
+                index = i;
+            }
+        }
+        if (max % 2 == 0)
+        {
+            return s.substr(index - max / 2 + 1, max);
+        }
+        return s.substr(index - max / 2, max);
+    }
+};