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.

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 [].

解题方法

1比较简单，只要找到"++"，将它们被替代后的结果加到List里就可以。

Solution

class Solution(object):
    def generatePossibleNextMoves(self, s):
        """
        :type s: str
        :rtype: List[str]
        """
        length = len(s)
        if length == 0 or length == 1:
            return []
        result = []
        for i in range(length-1):
            if s[i:i+2] == "++":
                newStr = s[:i] + "--" + s[i+2:]
                result.append(newStr)
        return result

Reference