Largest Number At Least Twice of Others.py

from typing import List


class Solution:
    """
    Time:   O(n)
    Memory: O(1)
    """

    def dominantIndex(self, nums: List[int]) -> int:
        first_max = second_max = -1
        max_ind = 0

        for i, num in enumerate(nums):
            if num >= first_max:
                first_max, second_max = num, first_max
                max_ind = i
            elif num > second_max:
                second_max = num

        if first_max < 2 * second_max:
            max_ind = -1

        return max_ind