2的次冪

package com.xiaobu.leetcode;

/**
 * @author xiaobu
 * @version JDK1.8.0_171
 * @date on  2019/10/23 16:51
 * @description 判斷一個整數是否爲2的次冪
 */
public class CheckPowerOfTwo {
    public static boolean isTwoPower(int n){
        if(n<=0){
            return false;
        }
        return (n & n - 1) == 0;
    }

    public static void main(String[] args) {
           boolean flag= isTwoPower(16);
        System.out.println("flag = " + flag);
    }


    public static boolean checkIsPowerOfTwoByRecursive(int n) {
        if (n == 1) {
            return true;
        }
        if (n == 0) {
            return false;
        }
        return checkIsPowerOfTwoByRecursive(n / 2) && n % 2 == 0;
    }
}