Nim Game

Leetcode

題意：

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.

解題思路：

其實只有在n為4的倍數時先手才會輸，其他不管怎麼樣，先手都會贏，因此只要判斷是否為4的倍數即可，程式碼如下：

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