367. Valid Perfect Square

Problem

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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

/**
 * @param {number} num
 * @return {boolean}
 */
var isPerfectSquare = function(num) {
  let num2 = 1,
  result = 0;

  while(result < num) {
    result = num2 ** 2;
    
    if (result == num) {
      return true;
    }

    num2++;
  }

  return false;
};