Add rust solution

2022/rust/.gitignore

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+target

2022/rust/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "aoc2022"
+version = "0.1.0"

2022/rust/Cargo.toml

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+[package]
+name = "aoc2022"
+version = "0.1.0"
+
+[[bin]]
+name = "day1"
+path = "src/day1.rs"
+
+[[bin]]
+name = "day2"
+path = "src/day2.rs"
+
+[dependencies]

2022/rust/fetch_input.sh

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+#!/usr/bin/env sh
+
+AOC_YEAR="${AOC_YEAR:-2022}"
+if [ "$#" -lt 1 ]; then
+  echo "Error: No day provided"
+  exit 1
+fi
+DAY="$1"
+f="$HOME/.cache/aoc$AOC_YEAR/$DAY.input"
+if [ -f "$f" ]; then
+  echo "Skip: File already exists"
+  exit 0
+fi
+url="https://adventofcode.com/$AOC_YEAR/day/$DAY/input"
+cookie="$(cat "$HOME/.advent-of-code-auth-cookie")"
+if curl --fail-with-body -X GET "$url" -H "Cookie:$cookie" > "$f"; then
+  echo "Downloaded $url to $f"
+  exit 0
+else
+  echo "Error: curl failed"
+  rm -f "$f"
+  exit 1
+fi

2022/rust/readme.md

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+# Rust Advent of Code 2022 Solutions
+
+I've been writing more Rust this year for an internal tool at work and have
+really enjoyed the tooling. I intent to do more with Rust this year than
+last and aim for good performance (without bending over too far backwards,
+anyways...)
+
+## Running
+
+First, you will want to fetch your input for the day you want to run. You will
+need `curl` and your Advent of Code cookie in `~/.advent-of-code-session-cookie`
+to run the following script:
+
+```bash
+fetch_input.sh 1
+```
+
+Where `1` is the day's input you want to fetch.
+
+### Debug
+
+```bash
+cargo run --bin day1
+```
+
+### Tests
+
+```bash
+cargo test --bin day1
+```
+
+### Release Mode
+
+For speeeeeed!
+
+```bash
+cargo build --release --bin day1
+time ./target/release/day1
+```

2022/rust/src/common.rs

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+use std::env::var as envvar;
+use std::fs;
+use std::path::Path;
+
+pub fn day_input(day: u8) -> String {
+    let home = &envvar("HOME").unwrap();
+    let home_path = Path::new(home);
+    let path_buf = home_path.join(format!("./.cache/aoc2022/{0}.input", day));
+    let file_path = path_buf.to_str().unwrap();
+    fs::read_to_string(file_path).unwrap()
+}

2022/rust/src/day1.rs

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+mod common;
+
+fn main() {
+    let calories = ordered_calories(&common::day_input(1));
+    println!("Part 1: {}", part1(&calories));
+    println!("Part 2: {}", part2(&calories));
+}
+
+fn ordered_calories(input: &str) -> Vec<i32> {
+    let mut result = Vec::from([0_i32]);
+    for l in input.lines() {
+        if l.trim() == "" {
+            result.push(0);
+        } else {
+            if let Ok(v) = l.parse::<i32>() {
+                *(result.last_mut().unwrap()) += v;
+            }
+        }
+    }
+    result.sort_by(|a, b| b.partial_cmp(a).unwrap());
+    result
+}
+
+fn part1(calories: &Vec<i32>) -> i32 {
+    calories[0]
+}
+
+fn part2(calories: &Vec<i32>) -> i32 {
+    calories.iter().take(3).sum()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const TEST_INPUT: &str = "1000
+2000
+3000
+
+4000
+
+5000
+6000
+
+7000
+8000
+9000
+
+10000";
+
+    fn test_calories() -> Vec<i32> {
+        ordered_calories(TEST_INPUT)
+    }
+
+    #[test]
+    fn test_part1() {
+        assert_eq!(part1(&test_calories()), 24000)
+    }
+
+    #[test]
+    fn test_part2() {
+        assert_eq!(part2(&test_calories()), 45000)
+    }
+}