367.py

# 367. Valid Perfect Square
# Given a positive integer num, return true if num is a perfect square or false otherwise.
# A perfect square is an integer that is the square of an integer.
# In other words, it is the product of some integer with itself.
# You must not use any built-in library function, such as sqrt.
# Example 1:
# Input: num = 16, Output: true
# Explanation: We return true because 4 * 4 = 16 and 4 is an integer.
# Example 2:
# Input: num = 14, Output: false
# Explanation: We return false because 3.742 * 3.742 = 14 and 3.742 is not an integer.

class Solution:
    def isPerfectSquare(self, num):
        low = 1
        high = num
        while low <= high:
            mid = (low + high) // 2
            if mid*mid == num:
                return True
            elif mid*mid < high:
                low = mid + 1
            else:
                high = mid - 1
        return False
solution = Solution()
num = 16
print(solution.isPerfectSquare(num))