add day2

2024/Cargo.toml

@@ -2,7 +2,7 @@
 resolver = "2"
 members = [
   "day1",
-  # "day2",
+  "day2",
   # "day3",
   # "day4",
   # "day5",

2024/day2/.gitignore

@@ -0,0 +1,19 @@
+input.txt
+flamegraph.svg
+perf.data*
+### Rust
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb
+

2024/day2/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "day2"
+authors = ["mirsella <[email protected]>"]
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+itertools = "0.13.0"
+

2024/day2/build.rs

@@ -0,0 +1,28 @@
+use std::fs::File;
+use std::io::{self, Read};
+use std::path::PathBuf;
+use std::{env, fs};
+
+fn replace_in_file(file_path: &PathBuf, old: &str, new: &str) -> io::Result<()> {
+    let mut contents = String::new();
+    File::open(file_path)?.read_to_string(&mut contents)?;
+    let new_contents = contents.replace(old, new);
+    if contents != new_contents {
+        println!("Updating {}", file_path.display());
+        fs::write(file_path, new_contents)?;
+    }
+    Ok(())
+}
+
+fn main() -> io::Result<()> {
+    let pkg_name = env::var("CARGO_PKG_NAME").unwrap();
+    replace_in_file(
+        &"../Cargo.toml".into(),
+        &format!("# \"{pkg_name}\""),
+        &format!("\"{pkg_name}\""),
+    )?;
+
+    replace_in_file(&"./Cargo.toml".into(), "\n[workspace]", "")?;
+
+    Ok(())
+}

2024/day2/src/main.rs

@@ -0,0 +1,68 @@
+use itertools::Itertools;
+
+fn part1(input: &str) -> usize {
+    input
+        .lines()
+        .map(|l| {
+            let levels = l
+                .split_whitespace()
+                .map(|n| n.parse::<usize>().unwrap())
+                .collect_vec();
+            let ordering = levels[0].cmp(&levels[1]);
+            levels
+                .into_iter()
+                .tuple_windows()
+                .all(|(a, b)| a.cmp(&b) == ordering && a.abs_diff(b) >= 1 && a.abs_diff(b) <= 3)
+        })
+        .filter(|v| *v)
+        .count()
+}
+fn part2(input: &str) -> usize {
+    input
+        .lines()
+        .map(|l| {
+            let levels = l
+                .split_whitespace()
+                .map(|n| n.parse::<usize>().unwrap())
+                .collect_vec();
+            (-1..levels.len() as isize).any(|i| {
+                let new_levels = if i < 0 {
+                    levels.clone()
+                } else {
+                    let mut l = levels.clone();
+                    l.remove(i as usize);
+                    l
+                };
+                let ordering = new_levels[0].cmp(&new_levels[1]);
+                new_levels
+                    .into_iter()
+                    .tuple_windows()
+                    .all(|(a, b)| a.cmp(&b) == ordering && a.abs_diff(b) >= 1 && a.abs_diff(b) <= 3)
+            })
+        })
+        .filter(|v| *v)
+        .count()
+}
+fn main() {
+    let input = include_str!("../input.txt");
+    println!("Part 1: {}", part1(input));
+    println!("Part 2: {}", part2(input));
+}
+
+#[cfg(test)]
+mod tests {
+    const INPUT: &str = "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";
+    #[test]
+    fn part1() {
+        assert_eq!(super::part1(INPUT), 2);
+    }
+    #[test]
+    fn part2() {
+        assert_eq!(super::part2(INPUT), 4);
+    }
+}