Find two numbers in a given array that add up to a specific target value, and return their indices. Essentially, you need to efficiently locate the pair that satisfies the sum requirement.

A list of directed connections forms a tree structure, but one extra connection has been added. This results in an error, like a node with two parents or a cycle. Find the single connection that can be removed to restore the tree.

Determine whether an integer is a palindrome. That is, it reads the same forwards and backward.