[Leetcode] 293. Flip Game 解题报告

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.

For example, given s = "++++", after one move, it may become one of the following states:

[
  "--++",
  "+--+",
  "++--"
]

If there is no valid move, return an empty list [].

思路：

很简单的一道题目，没有什么可讲的。估计follow up在后面。

代码：

class Solution {
public:
    vector<string> generatePossibleNextMoves(string s) {
        vector<string> ret;
        if (s.length() <= 1) {
            return ret;
        }
        for (int i = 0; i < s.length() - 1; ++i) {
            if (s[i] == '+' && s[i + 1] == '+') {
                ret.push_back(s);
                ret.back()[i] = ret.back()[i + 1] = '-';
            }
        }
        return ret;
    }
};