JacobLinCool's Solutions

231. Power of Two

Problem


Tags: Math, Bit Manipulation, Recursion

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

An integer n is a power of two, if there exists an integer x such that n == 2^x.

Example 1:

Input: n = 1
Output: true
Explanation: 20 = 1

Example 2:

Input: n = 16
Output: true
Explanation: 24 = 16

Example 3:

Input: n = 3
Output: false

Constraints:

  • -2^31 <= n <= 2^31 - 1

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

Code

JS

// 231. Power of Two (6/3/53941)
// Runtime: 80 ms (68.60%) Memory: 40.46 MB (94.98%) 

/**
 * @param {number} n
 * @return {boolean}
 */
function isPowerOfTwo(n) {
    return n > 0 && !(n & (n - 1));
}