power-of-two

Power of Two

LeetCode #: 231

Difficulty: Easy

Topics: Math, Bit Manipulation.

Problem

Given an integer, write a function to determine if it is a power of two.

Example 1:

Input: 1
Output: true 
Explanation: 2^0 = 1

Example 2:

Input: 16
Output: true
Explanation: 2^4 = 16

Example 3:

Input: 218
Output: false

Complexity Analysis

Time complexity: O(1)

Space complexity: O(1)