leetcode--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.

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.

思路：这道题提示当轮到我，石头数量为4时必输，引申一下，就是当轮到我，石头数为4n时(n>=2),这样对手一定能把石头降到4*(n-1)，这样递减，最后就可以保证到我时数量为4，必输。

硬编码请忽视。。

bool canWinNim(int n) {    if(n <= 0)    {        return false;    }    if(n % 4 == 0)    {        return false;    }    return true;}