Is Power of Three easy or hard?

Power of Three is classified as an Easy problem on most coding platforms. The logic relies on recognizing that powers of three contain only the prime factor 3 and verifying this using repeated division.

Power of Three Python/Java solution

In Python or Java, the typical solution uses a loop: while n % 3 == 0, divide n by 3. After the loop, check whether n equals 1. This approach runs in O(log n) time and works consistently across languages without precision issues.

How to solve Power of Three in O(1)?

A constant‑time approach uses logarithms. Compute k = log(n) / log(3) and check whether k is an integer. If the result is very close to an integer value, n can be represented as 3^k. This method runs in O(1) time but requires careful handling of floating‑point precision.

What is the best approach for Power of Three?

The iterative division approach is the most reliable solution. Repeatedly divide the number by 3 while it is divisible. If the value eventually becomes 1, the number is a power of three. This runs in O(log n) time with constant O(1) space and avoids floating‑point precision issues.

Is Power of Three asked at Google/Amazon/Meta?

Power of Three is a common warm‑up style interview problem used by companies like Google, Amazon, and Meta to test understanding of number properties and basic mathematical reasoning. It often appears in early interview rounds or coding assessments.

What data structure is used in Power of Three?

No specialized data structure is required. The problem is primarily a mathematical check using integer arithmetic. The typical implementation uses a loop and modulo operations to repeatedly divide the number by 3.

What is the time complexity of Power of Three?

The standard iterative solution runs in O(log₃ n) time because the number is divided by 3 in every iteration. Each step reduces the magnitude of n by a factor of three. Space complexity remains O(1) since only a single variable is updated.

Description Solution Video 3:16

326. Power of Three

Easy51.4% acceptance6 companies

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
Explanation: 27 = 3³

Example 2:

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

Example 3:

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

Constraints:

-2³¹ <= n <= 2³¹ - 1

Follow up: Could you solve it without loops/recursion?

Asked at 6 companies

Google Bloomberg Amazon Microsoft Meta Goldman Sachs

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Math Recursion

3:16

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326. Power of Three

Asked at 6 companies

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