Part 1: Given a list of strings, find the most common character in each position.

Part 1: Generate a series of hashes: MD5(salt + index). For each hash starting with five zeros, write down the sixth character.

Part 1: A room is described as a name, a sector ID, and a checksum as follows:

aaaaa-bbb-z-y-x-123[abxyz]

name: aaaaa-bbb-z-y-x
sector ID: 123
checksum: abxyz

A room is valid if the checksum contains the five most common letters if the name (ties broken alphabetically).

Part 1: Given a list of sides, determine how many form valid triangles. (Hint: triangle inequality)

Part 1: Take a keypad with the following layout:

1 2 3
4 5 6
7 8 9

Using the instructions UDLR for Up, Down, Left, and Right respectively, move a ‘finger’ around over the keypad. At the end of each line of instructions, output the current digit.

Part 1: Starting at 0,0 and given a string of L# / R# to turn left / right and move # squares, where do you end up?