lc292. Nim Game

292. Nim Game

You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be the winner. You will take the first turn to remove the stones.

Both of you are very clever and have optimal strategies for the game. Write a function to determine whether you can win the game given the number of stones in the heap.

Example:

Input: 4 Output: false Explanation: If there are 4 stones in the heap, then you will never win the game; No matter 1, 2, or 3 stones you remove, the last stone will always be removed by your friend. 思路: 反推，

1. n回合 輪到他石子數字爲4，我贏
2. n-1回合，輪到我石子數爲5-7，我能給他留4，我贏
3. n-2回合，輪到他石子數爲8，我贏 石子數目不爲4的倍數，我贏，不然，輸

代碼:python3

class Solution:
    def canWinNim(self, n: int) -> bool:
        if n%4 ==0:
            return False
        else:
            return True
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