326-3的幂

LeetCode 326. Power of Three

Given an integer n, return true if it is a power of three. Otherwise, return false.

An integer $n$ is a power of three, if there exists an integer $x$ such that $n = 3^x$.

Example 1:

Input: n = 27
Output: true

Example 2:

Input: n = 0
Output: false

method

试除法

bool isPowerOfThree(int n) {
    while (n && n % 3 == 0) {
        n /= 3;
    }
    return n == 1;
}