lleetcode 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.

本题中，由于你是第一个拿石子的人，所以，只要所有的石子数目为4的整数倍，那么就必然会输，因为你的对手可以保证在你拿走一次石子后，始终每次拿走石子的个数和你拿走石子的个数和为4。

class Solution {
public:
    bool canWinNim(int n) {
        if(n % 4 ==0)
            return false;
        else
            return true;
    }
};