Question

Intuition

Approach

Complexity

• Time complexity: $$O(log \ n)$$

• Space complexity: $$O(1)$$

Code

class Solution:
    def isPerfectSquare(self, num: int) -> bool:
        low, high = 0, num
        while (low <= high):
            mid = (low + high) // 2
            if mid * mid == num:
                return True
            elif mid * mid >= num:
                high = mid - 1
            else:
                low = mid + 1
        return False

Result