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.

很简单的一道题，对面拿1，我们就拿3，对面拿x，我们就拿4-x，这样就可以保证自己加对面一轮的和是4，所以第一轮拿原来的数对于4的余数就行了。当余数为0时我们拿不到0，这样就给对面机会了，所以只要n%4不为0就可以赢。

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