[LeetCode] 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.

For example, 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.

根据题意，有一堆石头，2个人轮流依次可以拿走1，2，3块石头。要使先拿石头的人取得胜利，则需要多少块石头。规律为 1，2，3，F，5，6，7，F，9，10，11，F，13...如果石头总数是4的倍数，则后拿石头的人一定会赢。

class Solution {
public:
    bool canWinNim(int n) {
        return n % 4 != 0;
    }
};
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