Staff member interview: 3 technical questions First shorten the word to an abbreviation (ie. "airport" --> "a5t") Second replace each letter with the digit '1' in each character (ie. "food" --> {"1ood", "f1od", "fo1d", "foo1"}) Third create abbreviated substrings of a given string (ie. "food" --> {"1ood", "f1od", "fo1d", "foo1", "2od", "f2d", "fo2", "3d", "f3", "4"}) System design question Design a database that stores every single possible phone number on the planet.