LeetCode 第 292 题 （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.

若干块石头，两个人交替取走一些，每次取只能取 1 到 3 颗。取到最后一块石头的人输。那么最优的策略是取走一些石头后剩下的石头是 4 的倍数。根据这个原则，这个题目就非常简单了。

bool canWinNim(int n) 
{
    return (n % 4 ！= 0);
}