A disguised topological sort problem. I was given a list of app actions like ["Swipe up to Home", "Search 'Photos'", "Tap on Search Bar", "Click Download", "Launch App"] and a set of order constraints like ["Launch App, Tap on Search Bar", "Tap on Search Bar, Search 'Photos'", "Click Download, Swipe up to Home"]. The task was to return any valid sequence of the actions that satisfied all the given constraints, outputting them as a single string joined by " - ".