LeetCode Flip Game II

 1 public class Solution {
 2     public boolean canWin(String s) {
 3         for(int i = 1; i<s.length(); i++){
 4             if(s.charAt(i-1) == ‘+‘ && s.charAt(i) == ‘+‘ && !canWin(s.substring(0,i-1) + "--" + s.substring(i+1))){
 5                 return true;
 6             }
 7         }
 8         return false;
 9     }
10 }