Problem - Next Greater Element I

You have two arrays $nums1$ and $nums2$ where $nums1$ is a subset of $nums2$. For each element in $nums1$, find its next greater element in $nums2$. Return $-1$ if there is none.

This problem has a twist: you need to find next greater elements in $nums2$, then look up the answers for elements in $nums1$. Use a monotonic stack on $nums2$, store results in a hash map, then query for $nums1$ elements.