LeetCode 1780. Check if Number is a Sum of Powers of Three

Given an integer n, return true if it is possible to represent n as the sum of distinct powers of three. Otherwise, return false.

An integer y is a power of three if there exists an integer x such that y == 3x.

Example 1:

Input: n = 12
Output: true
Explanation: 12 = 31 + 32

Example 2:

Input: n = 91
Output: true
Explanation: 91 = 30 + 32 + 34

Example 3:

Input: n = 21
Output: false

Constraints:

• 1 <= n <= 10^7

Solution:

class Solution {
public:
    bool checkPowersOfThree(int n) {
        int tmp = 3;
        while (tmp < n) {
            tmp *= 3;
        }
        
        while (tmp > 0) {
            if (n >= tmp) {
                n -= tmp;
            }
            tmp = tmp/3;
        }
        
        return n == 0;
    }
};