293. Flip Game 翻转游戏

• 作者： 负雪明烛
• id： fuxuemingzhu
• 个人博客：http://fuxuemingzhu.cn/

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题目地址：https://leetcode-cn.com/problems/flip-game/

题目描述

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 [].

题目大意

把给定字符串中的++换成--，返回所有可能的结果。

解题方法

遍历

题目表述不清，其实只要把所有++换成--即可，那就很简单了，直接遍历一次就行了。

C++代码如下：

class Solution {
public:
    vector<string> generatePossibleNextMoves(string s) {
        vector<string> res;
        if (s.empty() || s.size() == 1) return res;
        for (int i = 1; i < s.size(); ++i) {
            if (s[i] == '+' && s[i - 1] == '+') {
                string move = s;
                move[i] = move[i - 1] = '-';
                res.push_back(move);
            }
        }
        return res;
    }
};

日期

2019 年 9 月 19 日 —— 举杯邀明月，对影成三人