Given a non-empty binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any node in the tree along the parent-child ...

The ban on single-use plastic bags in Kenya was prefaced by vigorous sensitization campaigns undertaken by various international bodies like UNEP's Environment's Global Plastics Platform. These ...

Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below.