class Solution:
    def nextGreaterElement(self, nums1: List[int], nums2: List[int]) -> List[int]:
        stack = []  # mono stack of elements seen so far
        next_greater = {}

        for i in range(len(nums2) - 1, -1, -1):
            n = nums2[i]

            while stack and stack[-1] <= n:
                stack.pop()

            next_greater[n] = stack[-1] if stack else -1
            stack.append(n)

        return [next_greater[n] for n in nums1]