2023-07-23 17:18:00 +0000 UTC

class Solution:
    def arrangeCoins(self, n: int) -> int:
        left, right = 0, n

        while left <= right:
            middle = left + (right - left) // 2
            coins = middle * (middle + 1) // 2

            if coins == n:
                return middle
            
            if coins > n:
                right = middle - 1
            else:
                left = middle + 1
        
        return right