1 public class Solution { 2     public List
     
       generatePossibleNextMoves(String s) { 3         List
      
        result = new ArrayList<>(); 4         if (s.length() < 2) { 5             return result; 6         } 7          8         for (int i = 0; i < s.length() - 1; i++) { 9             if (s.charAt(i) == '+' && s.charAt(i+1) == '+') {10                 result.add(s.substring(0, i) + "--" + s.substring(i+2));11             }12         }13         return result;14     }15 }