Leetcode Flip Game II

You is playing the following Flip Game with your Friend:given a string this contains only these both characters: an + D - , you and your friend take turns to the flip twoconsecutive into "++" "--" . The game ends when a person can no longer make a move and therefore the other person would be the the winner.

Write a function to determine if the starting player can guarantee a win.

For example, given s = "++++" , return true. The starting player can guarantee a win by flipping the middle to "++" become "+--+" .

Follow up:
Derive your algorithm ' s runtime complexity.

Problem Solving Ideas:

Backtracking

Java Code

 Public class Solution {    publicboolean  Canwin (String s) {        for (int i = 0; I < S.length ()-1; i++) {            if(S.charat (i) = = ' + ' && s.charat (i+1) = = ' + ' &&!canwin (s.substring ( 0,i) + "--" + s.substring (i+2))                {returntrue;            }        }         return false ;    }}

Reference:

1. Https://leetcode.com/discuss/64330/4-line-java-solution

2. Https://leetcode.com/discuss/64357/memoization-3150ms-130ms-44ms-python

Leetcode Flip Game II