Pergunta de entrevista da empresa Qualtrics

Implement an iterator for a binary tree using any traversal, find all combinations of values in an array that sum to a given target value, find the smallest multiple of a number that only contains 0s 1s and 2s, determine if a number is a power of 2 iteratively and recursively, given (x,y) on pascal's triangle find the number belong to that coordinate, convert a binary tree to a doubly linked list, implement getAt(int index) and insertAt(int index, char value) for an unrolled linked list.