DEV Community

King coder
King coder

Posted on • Edited on

Day 43 of DSA Problem Solving

Q1. Power of Two

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 == 2x.

Example 

Input: n = 1 Output: true Explanation: 20 = 1
Enter fullscreen mode Exit fullscreen mode 
Input: n = 16 Output: true Explanation: 24 = 16
Enter fullscreen mode Exit fullscreen mode

Code 

 /** * @param {number} n * @return {boolean} */ var isPowerOfTwo = function(n) { if (n < 1) return false; if (n === 1) return true; if (n % 2 !== 0) return false; return isPowerOfTwo(n/2) };
Enter fullscreen mode Exit fullscreen mode

Q2. Power of Four

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 == 4x.

Example 

Input: n = 16 Output: true
Enter fullscreen mode Exit fullscreen mode 
Input: n = 5 Output: false
Enter fullscreen mode Exit fullscreen mode

Code 

/** * @param {number} n * @return {boolean} */ var isPowerOfFour = function(n) { if (n < 1) return false; if (n === 1) return true; if (n % 2 !== 0) return false; return isPowerOfFour(n/4) };
Enter fullscreen mode Exit fullscreen mode

Q3. Power of Three

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 == 3x.

Example 

Input: n = 27 Output: true Explanation: 27 = 33
Enter fullscreen mode Exit fullscreen mode 
Input: n = 0 Output: false Explanation: There is no x where 3x = 0.
Enter fullscreen mode Exit fullscreen mode

Code 

 /** * @param {number} n * @return {boolean} */ var isPowerOfThree = function(n) { if(n === 1) return true; if(n === 0) return false return isPowerOfThree(n/3) };
Enter fullscreen mode Exit fullscreen mode

Top comments (0)