You are given two lists of words. Find the number of words that appear exactly once in each of the two lists.

Simulate a robot's movement on an infinite grid based on a sequence of commands and obstacles. Determine the square of the robot's final Euclidean distance from the origin.

You are given an array and want to minimize the time to make its sum at most a given value. You can reorder the array elements strategically to achieve this minimum time.