Solution: Next Greater Element Using a Stack

Statement

Implement a next_greater_element() function that takes a list of integers, lst, as input and returns the next greater number for every element in the list.

The next greater number for a number lst[i] is the first number to its right that is greater than lst[i]. If no such number exists, return -1 for this number.

Constraints:

• $1 \leq$ lst.length $\leq 10^{3}$