Cream summer dress

Given a list of non-negative integers, find the minimum number of merge operations to make it a palindrome. A merge operation can only be performed on two adjacent elements and replace them with their sum.

In-place merge two height-balanced BSTs

Given two height-balanced binary search trees, in-place merge them into a single balanced binary search tree. For each node of a height-balanced tree, the difference between its left and right subtree height is at most 1.