Flip Game

给一个string里面是+和-, 求反转连续两个+后的所以可能string.

class Solution {
    public List<String> generatePossibleNextMoves(String s) {
        List<String> res = new ArrayList<>();
        StringBuilder sb = new StringBuilder(s);
        for(int i = 0 ; i+1 < sb.length(); i++) {
            if(sb.charAt(i) == '+' && sb.charAt(i+1) == '+') {
                StringBuilder t = new StringBuilder(s);
                t.setCharAt(i, '-');
                t.setCharAt(i+1, '-');
                res.add(t.toString());
            }
        }
        return res;
    }
}