https://leetcode-cn.com/problems/longest-palindromic-substring/
class Solution { public String longestPalindrome(String s) { if (s.length() < 1) { return s; } int[][] map = new int[s.length()][s.length()]; for (int i = 0; i < s.length(); i++) { map[i][i] = 1; } char[] sChar = s.toCharArray(); int maxLength = 1; int maxL = 0; int maxR = 0; for (int lenght = 2; lenght <= s.length(); lenght++) { for (int i = lenght - 1; i < s.length(); i++) { int k = i - lenght + 1; char char2 = sChar[k]; char char1 = sChar[i]; String string = s.substring(k, i + 1); if (sChar[k] == sChar[i] && (k + 1 > i - 1 || map[k + 1][i - 1] != 0)) { if ((map[k][i] = map[k + 1][i - 1] + 2) > maxLength) { maxL = k; maxR = i; } } } } return s.substring(maxL, maxR + 1); } }