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.

给一堆石头，俩个人拿，你是先手，一次只能拿1-3个，最后拿不到的输。
这道题还是很简单的，因为一次只能拿1-3个，所以如果是4个石头，你先手就肯定输

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

这是一个博弈问题，这一系列还有很多问题，有机会的话再做总结。