LeetCode - 292 Nim Game

问题

思路

提交

TLE

public class Solution {

    public boolean canWinNim(int n) {
        if (n <= 3) {
            return true;
        }
        boolean canWin1 = true;
        boolean canWin2 = true;
        boolean canWin3 = true;
        for (int i = 4; i <= n; i++) {
            boolean t = canWin3;
            if (canWin1 && canWin2 && canWin3) {
                canWin3 = false;
            } else {
                canWin3 = true;
            }
            canWin1 = canWin2;
            canWin2 = t;
        }
        return canWin3;
    }
}

O(n) 时间复杂度，直接 TLE 了！好吧，稍微归纳一下实际上很简单 O(1)

public class Solution {

    public boolean canWinNim(int n) {
        if (n <= 3) {
            return true;
        }
        return n % 4 != 0;
    }
}