leetcode-342-Power-of-Four

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描述

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example:

Given num = 16, return true. Given num = 5, return false.

Follow up: Could you solve it without loops/recursion?

分析

和那道2的n次幂，用log函数即可。

解决方案1(C++)

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class Solution {
public:
    bool isPowerOfFour(int num) {
        if(num <= 0) {
            return false;
        }else {
            return (log(num)/log(4)) == (int)(log(num)/log(4));
        }
    }
};

相关问题

(E) Power of Two
(E) Power of Three

题目来源