747. Largest Number At Least Twice of Others

Problem Link

Description

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You are given an integer array nums where the largest integer is unique.

Determine whether the largest element in the array is at least twice as much as every other number in the array. If it is, return the index of the largest element, or return -1 otherwise.

 

Example 1:

Input: nums = [3,6,1,0]
Output: 1
Explanation: 6 is the largest integer.
For every other number in the array x, 6 is at least twice as big as x.
The index of value 6 is 1, so we return 1.

Example 2:

Input: nums = [1,2,3,4]
Output: -1
Explanation: 4 is less than twice the value of 3, so we return -1.

 

Constraints:

• 2 <= nums.length <= 50
• 0 <= nums[i] <= 100
• The largest element in nums is unique.

Solution

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Python3

class Solution:
    def dominantIndex(self, nums: List[int]) -> int:
        
        highestindex, h1, h2 = 0, -1, -1
        
        for i,num in enumerate(nums):
            if num > h1:
                h2 = h1
                h1 = num
                highestindex = i
                
            elif num > h2 and num < h1:
                h2 = num
                
        return highestindex if h1 >= h2*2 else -1