Completed day 1

day01/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "anyhow"
+version = "1.0.51"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b26702f315f53b6071259e15dd9d64528213b44d61de1ec926eca7715d62203"
+
+[[package]]
+name = "day01"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+]

day01/Cargo.toml

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+[package]
+name = "day01"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0"

day01/input/test.txt

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+199
+200
+208
+210
+200
+207
+240
+269
+260
+263

day01/src/main.rs

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+use std::fs::File;
+use std::io::prelude::*;
+use std::io::BufReader;
+use std::time::Instant;
+
+use anyhow::Result;
+
+const INPUT: &str = "input/input.txt";
+
+fn solve_part1(input_path: &str) -> Result<i32> {
+    let file = File::open(input_path)?;
+    let reader = BufReader::new(file);
+
+    let mut increases = 0;
+    let mut prev_reading: Option<i32> = None;
+    for line in reader.lines() {
+        let reading = line?.parse()?;
+        if let Some(prev) = prev_reading {
+            if reading > prev {
+                increases += 1;
+            }
+        }
+        prev_reading = Some(reading);
+    }
+
+    Ok(increases)
+}
+
+fn solve_part2(input_path: &str) -> Result<i32> {
+    let file = File::open(input_path)?;
+    let reader = BufReader::new(file);
+
+    let mut increases = 0;
+    let mut prev_sum: Option<i32> = None;
+    let all_lines = reader
+        .lines()
+        .collect::<Result<Vec<String>, std::io::Error>>()?;
+    for lines in all_lines.windows(3) {
+        let sum = lines.iter().map(|s| s.parse::<i32>().unwrap()).sum();
+        if let Some(prev) = prev_sum {
+            if sum > prev {
+                increases += 1;
+            }
+        }
+        prev_sum = Some(sum);
+    }
+
+    Ok(increases)
+}
+
+fn main() {
+    let mut now = Instant::now();
+    println!("Part 1: {}", solve_part1(INPUT).unwrap());
+    println!("(elapsed: {:?})", now.elapsed());
+    now = Instant::now();
+    println!("");
+    println!("Part 2: {}", solve_part2(INPUT).unwrap());
+    println!("(elapsed: {:?})", now.elapsed());
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const TEST_INPUT: &str = "input/test.txt";
+
+    #[test]
+    fn solves_part1() {
+        assert_eq!(solve_part1(TEST_INPUT).unwrap(), 7);
+    }
+
+    #[test]
+    fn solves_part2() {
+        assert_eq!(solve_part2(TEST_INPUT).unwrap(), 5);
+    }
+}