README.md

Day 02 - Red-Nosed Reports

Note

Input link: https://adventofcode.com/2024/day/2/input

Part 1

Note

Problem link: https://adventofcode.com/2024/day/2

The unusual data (your puzzle input) consists of many reports, one report per line. Each report is a list of numbers called levels that are separated by spaces. For example:

7 6 4 2 1
1 2 7 8 9
9 7 6 2 1
1 3 2 4 5
8 6 4 4 1
1 3 6 7 9

This example data contains six reports each containing five levels.

The engineers are trying to figure out which reports are safe. The Red-Nosed reactor safety systems can only tolerate levels that are either gradually increasing or gradually decreasing. So, a report only counts as safe if both of the following are true:

• The levels are either all increasing or all decreasing.
• Any two adjacent levels differ by at least one and at most three.

Analyze the unusual data from the engineers. How many reports are safe?

Part 1 Solution

$ cargo run --release -- --input 2024/day02/input.txt 2024 02 part1
252

Part 2

Note

Problem link: https://adventofcode.com/2024/day/2#part2

Now, the same rules apply as before, except if removing a single level from an unsafe report would make it safe, the report instead counts as safe.

Part 2 Solution

$ cargo run --release -- --input 2024/day02/input.txt 2024 02 part2
324