🎄 Advent of Code 2015

Solutions for Advent of Code in Rust.

2015 Results

Day	Part 1	Part 2
Day 1	⭐	⭐
Day 2	⭐	⭐
Day 3	⭐	⭐
Day 4	⭐	⭐
Day 5	⭐	⭐
Day 6	⭐	⭐
Day 7	⭐	⭐

---

Usage

Scaffolding files and downloading puzzle input

cargo scaffold 1 --download   # Create scaffolding for day 1 and download puzzle input
cargo scaffold 1              # Create scaffolding for day 1
cargo download 1              # Download puzzle input for day 1
cargo read 1                  # Read puzzle description for day 1

Testing

cargo test
cargo test --bin 01
cargo test --bin 01 part_one

Debugging

1. Install the rust-analyzer and CodeLLDB extensions
2. Set breakpoints in your code
3. Click Debug next to the unit test or the main function
4. The debugger will halt your program at the specific line and allow you to inspect the local stack

Running and submitting

cargo solve 1              # Run day 1 solution against real puzzle inputs
cargo solve 1 2            # Run day 1, part 2 solution against real puzzle inputs
cargo solve 1 2 --release  # Run day 1, part 2 solution against real puzzle inputs with an optimized build
cargo all                  # Run all solutions sequentially
cargo all --release        # Run all solutions sequentially with optimized build
cargo solve 1 --submit 2   # Submit day 1, part 2 solution

Benchmarking

cargo time 1              # Run day 1 10-10K times (depending on execution time) and print the average runtime
cargo time --all          # Print the average runtime for all days
cargo solve 1 --dhat      # Analyze day 1 heap allocations with DHAT (https://valgrind.org/docs/manual/dh-manual.html)
cargo time 1 --store      # Add day 1 timings to the readme
cargo time --all --store  # Add all timings to the readme

The --dhat command will output some basic stats to the command-line and generate a dhat-heap.json report in the repo root directory. You can pass the report a tool like dh-view to view a detailed breakdown of heap allocations.

Linting and formatting

cargo fmt
cargo clippy

Session cookie for AOC CLI

1. Copy the session 🍪 from the AOC website (you'll find it under Cookies in the Application or Storage tab)
2. Create a $HOME/.adventofcode.session file and paste the 🍪 there
3. Create an AOC_SESSION repo secret and paste the 🍪 there as well (Settings -> Secrets -> New repository secret)
4. When the 🍪 expires, repeat steps 1-3, replacing the old value with the new one

Common pitfalls

• Whitespace in input: Make sure the input file has no leading or trailing whitespace, including no newline at the end of the file.
• Integer overflows: This template uses 32-bit integers by default because it is generally faster - for example when packed in large arrays or structs - than using 64-bit integers everywhere. For some problems, solutions for real input might exceed 32-bit integer space. While this is checked and panics in debug mode, integers wrap in release mode, leading to wrong output when running your solution.