Valid Perfect Square — LeetCode 367 Python Solution

The problem

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.

Example

Input

num = 16

Output

true

Explanation

We return true because 4 * 4 = 16 and 4 is an integer.

Python solution

class Solution:
    def isPerfectSquare(self, num: int) -> bool:
        l = bisect_left(range(1, num + 1), num, key=lambda x: x * x) + 1
        return l * l == num

Complexity

Pattern: Monotonic Stack

Answer "what is the next greater element" for every position in one pass. LeetCode 367. Valid Perfect Square is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The monotonic stack guide has the Python template for the pattern and the 225 LeetCode problems that use it.

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