Is Power of Four easy or hard?

Power of Four is classified as an Easy problem. The logic mainly involves recognizing mathematical patterns or simple division loops. Despite the difficulty rating, it often appears in interviews to check understanding of number properties.

Power of Four Python/Java solution

In Python or Java, the common solution repeatedly divides the number by 4 while n % 4 == 0. After the loop, check whether n equals 1. This implementation runs in O(log n) time and O(1) space.

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

Use the logarithmic property of powers: compute log(n) / log(4) and check if the result is an integer. If the value equals its integer form (within floating‑point tolerance), the number is a power of four. This method performs constant-time calculations, giving O(1) time complexity.

What is the best approach for Power of Four?

The iterative division approach is typically the best choice. Repeatedly divide the number by 4 while it remains divisible, then check if the final value becomes 1. This runs in O(log n) time with O(1) space and avoids floating‑point precision issues that appear in logarithmic solutions.

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

Power of Four appears in coding interviews at major tech companies because it tests understanding of number properties and bit patterns. Variants involving powers of two or bit manipulation are common at companies like Google, Amazon, and Meta.

What data structure is used in Power of Four?

The problem does not require complex data structures. It relies on arithmetic checks or mathematical properties. Some optimized variants use bit manipulation to inspect binary patterns of powers of four.

What is the time complexity of Power of Four?

The iterative division method runs in O(log n) time because the value is divided by 4 each iteration. The logarithmic formula approach runs in O(1) time since it performs only a few mathematical operations. Both use O(1) space.

342. Power of Four - Practice Online

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

An integer n is a power of four, if there exists an integer x such that n == 4^x.

Example 1:

Input: n = 16
Output: true

Example 2:

Input: n = 5
Output: false

Example 3:

Input: n = 1
Output: true

Constraints:

-2³¹ <= n <= 2³¹ - 1

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