[LeetCode 326] Power of Three

문제 바로가기

Description

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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

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• Input: n = 27
• Output: true
• Explanation: 27 = 3^3

Example 2

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• Input: n = 0
• Output: false
• Explanation: There is no x where 3^x = 0.

Example 3

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• Input: n = -1
• Output: false
• Explanation: There is no x where 3^x = (-1).

Constraints

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• -2^31 <= n <= 2^31 - 1

Code

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내 제출

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class Solution {
    public boolean isPowerOfThree(int n) {
        while (n > 2) {
            if (n % 3 != 0) {
                return false;
            }
            n /= 3;
        }
        return n == 1;
    }
}

Runtime	Memory
8 ms	43.6 MB

다른 풀이

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class Solution {
    public boolean isPowerOfThree(int n) {
        if(n<=0)
        return false;
        while(n%3==0)
        {
            n=n/3;
        }
        return n==1;
    }
}

Reference

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• https://github.com/doocs/leetcode/blob/main/solution/0300-0399/0326.Power%20of%20Three/Solution.java