Update README.md

Author: yanglbme

solution/0000-0099/0005.Longest Palindromic Substring/README.md

@@ -277,6 +277,42 @@ public class Solution {
 }
 ```
 
+#### C
+
+```c
+char* longestPalindrome(char* s) {
+    int n = strlen(s);
+    bool** f = (bool**) malloc(n * sizeof(bool*));
+    for (int i = 0; i < n; ++i) {
+        f[i] = (bool*) malloc(n * sizeof(bool));
+        for (int j = 0; j < n; ++j) {
+            f[i][j] = true;
+        }
+    }
+    int k = 0, mx = 1;
+    for (int i = n - 2; ~i; --i) {
+        for (int j = i + 1; j < n; ++j) {
+            f[i][j] = false;
+            if (s[i] == s[j]) {
+                f[i][j] = f[i + 1][j - 1];
+                if (f[i][j] && mx < j - i + 1) {
+                    mx = j - i + 1;
+                    k = i;
+                }
+            }
+        }
+    }
+    char* res = (char*) malloc((mx + 1) * sizeof(char));
+    strncpy(res, s + k, mx);
+    res[mx] = '\0';
+    for (int i = 0; i < n; ++i) {
+        free(f[i]);
+    }
+    free(f);
+    return res;
+}
+```
+
 #### Nim
 
 ```nim
@@ -527,55 +563,6 @@ class Solution {
 }
 ```
 
-#### c
-
-```c
-char *longestPalindrome(char *s) {
-  int n = strlen(s);
-  if (n == 0) {
-    char *result = malloc(1);
-    result[0] = '\0';
-    return result;
-  }
-
-  bool dp[n][n];
-  memset(dp, 0, sizeof(dp));
-
-  int start = 0, max_len = 1;
-
-  for (int i = 0; i < n; i++) {
-    dp[i][i] = true;
-  }
-
-  for (int i = 0; i < n - 1; i++) {
-    if (s[i] == s[i + 1]) {
-      dp[i][i + 1] = true;
-      start = i;
-      max_len = 2;
-    }
-  }
-
-  // Check for lengths > 2
-  for (int len = 3; len <= n; len++) {
-    for (int i = 0; i < n - len + 1; i++) {
-      int j = i + len - 1;
-      if (s[i] == s[j] && dp[i + 1][j - 1]) {
-        dp[i][j] = true;
-        if (len > max_len) {
-          start = i;
-          max_len = len;
-        }
-      }
-    }
-  }
-  char *result = malloc(max_len + 1);
-  strncpy(result, s + start, max_len);
-  result[max_len] = '\0';
-  return result;
-}
-
-```
-
 <!-- tabs:end -->
 
 <!-- solution:end -->