<span style="font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; background-color: rgb(255, 255, 255);">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.</span>
 

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.

解題思路：要讓自己贏，只要再最後一輪剩4個，所有第一次拿的話，拿掉4的餘數，剩下的每輪，無論對手拿掉幾個，我都保證一共拿掉4個。但是，如果給的數目是4的倍數的話，就不能保證自己贏。

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