The fourth and hardest coding question: "Given a square grid of numbers, print out the longest 'snake sequence'. A snake sequence is a sequence of adjacent (not diagonal) numbers such that each number is within +-1 of its neighbors in the sequence. Snake sequences can only go down and right. If there are multiple snake sequences of largest length, print out them all."
Third question: "You are given a sequence of numbers like 1234. You know that each number can map to a certain amount of keys; for example, 2 can map to [w,s,x], and 3 can map to [e,d,c]. Print out every possible sequence of characters that the sequence of numbers might correspond to."
Don't remember the second question.
First question: "Someone is entering a code on a keypad, but (at most) one of the keys is intermittently faulty. Therefore, there is some lenience about what code is entered. If a number is missing in the input, the keypad still accepts it, provided that all other numbers are present and in their proper place. If the passcode is 11223311, then valid inputs would include 1223311, 2233, 112211, and 11223311, but not 112311."