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Write a function that takes in a Binary Tree and returns a list of its branch sums ordered from leftmost branch sum to rightmost branch sum.

Given an array of integers between 1 and n, inclusive, where n is the length of the array, write a function that returns the first integer that appears more than once (when the array is read from left to right).

Write a function that takes in an array of integers and returns the length of the longest peak in the array.

You're given a non-empty array of positive integers representing the amounts of time that specific queries take to execute. Only one query can be executed at a time, but the queries can be executed in any order.

Write a function that takes in an array of integers and returns a new array containing, at each index, the next element in the input array that's greater than the element at that index in the input array.

Write a function that takes in an n x m two-dimensional array (that can be square-shaped when n == m) and returns a one-dimensional array of all the array's elements in spiral order.

You're given an array of integers and another array of three distinct integers. The first array is guaranteed to only contain integers that are in the second array, and the second array represents a desired order for the integers in the first array. For example, a second array of [x, y, z] represents a desired order of [x, x, ..., x, y, y, ..., y, z, z, ..., z] in the first array.

Given two non-empty arrays of integers, write a function that determines whether the second array is a subsequence of the first one.

You're given three inputs, all of which are instances of an AncestralTree class that have an ancestor property pointing to their youngest ancestor. The first input is the top ancestor in an ancestral tree (i.e., the only instance that has no ancestor--its ancestor property points to None / null), and the other two inputs are descendants in the ancestral tree.

Write a function that takes in a non-empty array of arbitrary intervals, merges any overlapping intervals, and returns the new intervals in no particular order.