342. Power of Four
难度: Easy
刷题内容
原题连接
- https://leetcode.com/problems/power-of-four
内容描述
Given an integer (signed 32 bits), write a function to check whether it is a power of 4.
Example 1:
Input: 16
Output: true
Example 2:
Input: 5
Output: false
Follow up: Could you solve it without loops/recursion?
解题方案
思路 1 **- 时间复杂度: O(1)*- 空间复杂度: O(1)***
recursive
class Solution {
public boolean isPowerOfFour(int num) {
if (num <= 0)
return false;
if (num == 1)
return true;
if (num % 4 == 0)
return isPowerOfFour(num/4);
return false;
}
}
