2018-07-25 14:03:46 +0000   |     algorithm leetcode string   |   Viewed times   |    

题目

You are playing the following Flip Game with your friend: Given a string that contains only these two characters: “+” and “-“, you and your friend take turns to flip two consecutive “++” into “–”. The game ends when a person can no longer make a move and therefore the other person will be the winner.

Write a function to compute all possible states of the string after one valid move.

Example:

Input: s = "++++"
Output:
[
  "--++",
  "+--+",
  "++--"
]

Note: If there is no valid move, return an empty list “[]”.

遍历字符串,找到”–“即替换成”++”

代码

class Solution {
    public List<String> generatePossibleNextMoves(String s) {
        List<String> res = new ArrayList<>();
        for (int i = 0; i < s.length()-1; i++) {
            if (s.charAt(i) == '+' && s.charAt(i+1) == '+') {
                res.add(s.substring(0,i) +
                        "--" +
                        s.substring(i+2,s.length()));
            }
        }
        return res;
    }
}

结果

flip-game-1