367. Valid Perfect Square

 Given a positive integer num, write a function which returns True if num is a perfect square else False.

Follow up: Do not use any built-in library function such as sqrt.

 

Example 1:

Input: num = 16
Output: true

Example 2:

Input: num = 14
Output: false

 

Constraints:

• 1 <= num <= 2^31 - 1

Solution:

In JS:

var isPerfectSquare = function(num) {

   for(let index = 0; index <= parseInt(Math.sqrt(num))+1; index++){

      let perfectSqrt = index * index;

      if(perfectSqrt === num) return true

    }

    return false;

};