Swift算法9-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.

*** if there are 4 stones, you will never win!!! 大写加粗！！！
所以你第一步走的话就可以先把石头总数除以4的余数个数的石头拿走，这样剩余的石头就是若干个4个石头，对手先走的游戏了，于是你可以always win，但是如果石头总数可以被4整除，那你就永远不会赢。

class Solution {
    func canWinNim(n: Int) -> Bool {
       return n % 4 != 0 
    }
}