[LeetCode_5] Longest Palindromic Substring

LeetCode: 5. Longest Palindromic Substring

class Solution {
public:
//动态规划算法
  string longestPalindrome(string s) {
    int n = s.length();
    int longestBegin = 0;
    int maxLen = 1;
    bool table[1000][1000] = {false};
    for (int i = 0; i < n; i++) {
      table[i][i] = true;
    }//对角设为1
    for (int i = 0; i < n-1; i++) {
      if (s[i] == s[i+1]) {
        table[i][i+1] = true;
        start = i;
        maxLen = 2;
      }
    }//检查是否存在"aa"这样的
    
    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] && table[i+1][j-1]) {
          table[i][j] = true;
          start = i;
          maxLen = len;
        }
      }
    }
    return s.substr(start, maxLen);
  }
};