一、题目
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 == 3x.
Example 1:
Input: n = 27
Output: true
Explanation: 27 = 33
Example 2:
Input: n = 0
Output: false
Explanation: There is no x where 3x = 0.
Example 3:
Input: n = -1
Output: false
Explanation: There is no x where 3x = (-1).
Constraints:
-231 <= n <= 231 - 1
Follow up: Could you solve it without loops/recursion?
二、题解
class Solution {
public:
bool isPowerOfThree(int n) {
return n > 0 && 1162261467 % n == 0;
}
};
