647. 回文子串
boolean默认类型是false
class Solution {public int countSubstrings(String s) {if(s == null) return 0;int result = 0;int length = s.length();boolean[][] dp = new boolean[length][length];for(int j=0;j<length;j++){for(int i=0;i<=j;i++){if(s.charAt(i) == s.charAt(j)){if(j-i<3){dp[i][j] = true;// result++;}else{dp[i][j] = dp[i+1][j-1];}}else{dp[i][j] = false;}}}for(int i=0;i<length;i++){for(int j=0;j<length;j++){if(dp[i][j] == true) result++;}}return result;}
}