AoC 2016 Day 7: IPv7 Support Counter

2016-12-07

Source: Internet Protocol Version 7

Part 1: The input is a list of strings, potentially containing sequences in square brackets. Find all strings that have an ABBA sequence (two characters followed by the same two in reverse order) outside of any square brackets, but no ABBA sequences in square brackets.

AoC 2016 Day 6: Signal Unjammer

2016-12-06

Source: Signals and Noise

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

AoC 2016 Day 5: Password Cracker

2016-12-05

Source: How About a Nice Game of Chess?

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

AoC 2016 Day 4: Room Validator

2016-12-04

Source: Security Through Obscurity¹

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

AoC 2016 Day 3: Triangle Validator

2016-12-03

Source: Squares With Three Sides

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

AoC 2016 Day 2: Pin Typer

2016-12-02

Source: Bathroom Security

Part 1: Take a keypad with the following layout:

1 2 3 4 5 6 7 8 9

AoC 2016 Day 1: Taxicab Simulator

2016-12-01

Source: No Time for a Taxicab

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?

Advent of Code: Day 25

2015-12-25

Source

Part 1: Take the relation:

F(n) = \left\{\begin{matrix} 20151225 & \textrm{if}\ n = 1 \\ 252533F(n-1) \mod 33554393 & \textrm{otherwise} \end{matrix}\right.

Arrange the values according to Cantor's diagonal argument. Find the value at a specific cell.

Advent of Code: Day 24

2015-12-24

Source

Part 1: Split a list of integers into three groups of equal sum. Find the grouping such that the smallest group has the least items, breaking ties by the smallest product for that group.