Trees

Given the roots of a binary tree, find the maximum depth of the tree by traversing its nodes in a way that explores as far as possible along each branch before backtracking.

Given the root of a binary tree and two nodes p and q that are present in it, return their lowest common ancestor — the deepest node that has both p and q as descendants (a node may be a descendant of itself).

Given a binary tree, write a solution to return the rightmost node at each level of the tree, representing the right side view of the tree.

Implement a BSTIterator over the in-order traversal of a binary search tree. next() returns the next smallest value in the tree, and hasNext() returns whether a next value exists. The iterator starts positioned before the smallest element.

Given the root of a binary tree where every node holds a single digit (0-9), each root-to-leaf path spells a number (for example the path 1 -> 2 -> 3 represents 123). Return the sum of these numbers over all root-to-leaf paths.