# AoC 2018 Day 5: Alchemical reduction

### Source: Alchemical Reduction

Part 1: Given a string, reduce it by removing pairs of letters that are the same letter but different cases. Repeat until you have a minimal string.

# AoC 2018 Day 4: Sleeping on the job

### Source: Repose Record

Part 1: Given a log of guard shifts and times asleep/awake, calculate the guard that was asleep most often and which minute they were most asleep for.

# AoC 2018 Day 3: Regionification

### Source: No Matter How You Slice It

Part 1: Given a list of overlapping regions defined by (left, top, width, height) count how many integer points occur in more than one region.

# AoC 2018 Day 2: Counting letters

### Source: Inventory Management System

Part 1: Given a list of strings, count how many contain exactly two of a letter (a) and how many contain exactly three of a letter (b). Calculate a*b.

### Source: Chronal Calibration

Part 1: Given a list of numbers (positive and negative) calculate the sum.