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 determine if the starting player can guarantee a win. Example: Input: s = "++++" Output: true Explanation: The starting player can guarantee a win by flipping the middle "++" to become "+--+". Follow up:?Derive your algorithm‘s runtime complexity. https://leetcode.com/problems/flip-game-ii/discuss/73954/Theory-matters-from-Backtracking(128ms)-to-DP-(0ms)
原文：https://www.cnblogs.com/tobeabetterpig/p/9914472.html