2021 Day 1 Rust

2021/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 = "rust"
+version = "0.1.0"

2021/rust/Cargo.toml

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+[package]
+name = "rust"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2021/rust/src/main.rs

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+mod utils;
+mod solutions;
+
+
+fn main() {
+    solutions::day01::run();
+}

2021/rust/src/solutions/day01.rs

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+use crate::utils;
+use crate::utils::Day;
+
+
+pub fn run() -> () {
+    let data = parse_data(utils::read_lines(Day(1)));
+
+    println!("Day 1");
+    println!("Part 1: {}", solve1(&data));
+    println!("Part 2: {}", solve2(&data));
+}
+
+fn solve1(lines: &Vec<i32>) -> i32 {
+    let mut increments = 0;
+    let mut prev = i32::MAX;
+    for &n in lines {
+        if n > prev { increments += 1 };
+        prev = n;
+    };
+    increments
+}
+
+fn solve2(lines: &Vec<i32>) -> i32 {
+    let length = lines.len();
+
+    let left = lines[..length - 1].windows(3);
+    let right = lines[1..].windows(3);
+
+
+    left.zip(right)
+        .fold(0, |acc, (left, right)| {
+            let sum_left: i32 = left.iter().sum();
+            let sum_right: i32 = right.iter().sum();
+            acc + if sum_left < sum_right { 1 } else { 0 }
+        })
+}
+
+fn parse_data(lines: Vec<String>) -> Vec<i32> {
+    lines.iter()
+        .map(|x| x.parse())
+        .collect::<Result<Vec<i32>, _>>()
+        .expect("Failed to parse int")
+}

2021/rust/src/solutions/mod.rs

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+pub mod day01;

2021/rust/src/utils.rs

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+use std::fs::File;
+use std::io::{BufRead, BufReader};
+use std::path::Path;
+
+
+#[repr(transparent)]
+pub struct Day(pub i32);
+
+
+pub fn read_lines(day: Day) -> Vec<String> {
+    assert!(1 <= day.0 && day.0 < 25);
+    _read_lines(format!("inputs/day{:0>2}.txt", day.0))
+        .expect(format!("Failed to load day {}", day.0).as_str())
+}
+
+fn _read_lines<P>(filename: P) -> std::io::Result<Vec<String>>
+    where P: AsRef<Path> {
+    let file = File::open(filename)?;
+    BufReader::new(file).lines().collect()
+}