Power Of Two · Interview Problem

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Leetcode

Easy

Bit Manipulation

Math

Power Of Two

Determine whether an integer is an exact power of two.

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Power of 2

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Problem Statement

Given an integer n, return whether it can be written in the form 2^k for some integer k >= 0.

A number is a power of two if it is positive and has exactly one set bit in its binary representation.

Input Format

A single integer n.
Decide whether n is a power of two.

Output Format

Return true if n is an exact power of two.
Otherwise return false.

Constraints

You may assume n fits in a standard 32-bit signed integer.
n may be non-positive.
Aim for $O(1)$ or $O(\log n)$ time.

Examples

Sample cases returned by the problem API.

Example 1

Input

n = 1

Output

true

Explanation

$1 = 2^0$ .

Example 2

Input

n = 16

Output

true

Explanation

$16 = 2^4$ .

Show 1 more example

Example 3

Input

n = 3

Output

false

Explanation

3 is not an exact power of two.

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