Problem: Largest Number At Least Twice of Others

Statement

Given an integer array nums, in which the largest element is guaranteed to be unique, determine whether this largest element is at least twice as large as every other element in the array.

If the condition holds, return the index of the largest element. Otherwise, return $-1$.

Constraints:

• $2 \leq$ nums.length $\leq 50$

• $0 \leq$ ...