293_Flip_Game

Flip Game

Difficulty Easy

tags array

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:

greedy

失误的case:

1. 这道题存在的意义就是提醒同学们 .size() 返回的是一个无符号数，对它进行操作没有考虑下溢的时候，你就GG了。

solution 1

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