input: Write a python function to determine if a given number is a perfect square.
  assert check_perfect_square(10) == False
  assert check_perfect_square(36) == True
  assert check_perfect_square(14) == False
output: def check_perfect_square(num):
      if num < 0:
          return False
      root = int(num ** 0.5)
      return root * root == num