Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You may assume no duplicates in the array.

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 ...

Photos, left to right: After school program in Honduras, courtesy of Honduran Youth Alliance/Alianza Joven Honduras; U.S. Border Patrol Agent training Guatemalan Police, by Miguel Negronvia ...