2021/src/day2.rs

@@ -1,86 +0,0 @@
-use std::str::FromStr;
-
-use color_eyre::eyre;
-use eyre::{eyre, ensure};
-
-use crate::lib::ParseLines;
-
-
-enum Direction {
-    Forward,
-    Up,
-    Down,
-}
-
-
-struct MoveCmd {
-    dir: Direction,
-    value: i32,
-}
-
-
-impl<'a> FromStr for MoveCmd {
-    type Err = eyre::Report;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let parts: Vec<&str> = s.split_whitespace().collect();
-        ensure!(parts.len() == 2, "Could not parse: \"{}\" (Wrong number of words)", s);
-
-        let dir = match parts[0] {
-            "forward" => Direction::Forward,
-            "up" => Direction::Up,
-            "down" => Direction::Down,
-            _ => return Err(eyre!("Could not parse: \"{}\" (invalid axis)", s)),
-        };
-
-        let value = parts[1].parse::<i32>()?;
-
-        Ok(MoveCmd{dir, value})
-    }
-}
-
-
-fn part1(commands: &Vec<MoveCmd>) -> i32 {
-    let mut horiz = 0; // how many units forward
-    let mut vert = 0; // how many units DOWN (so flipped)
-    for cmd in commands {
-        match cmd.dir {
-            Direction::Forward => horiz += cmd.value,
-            Direction::Up => vert -= cmd.value,
-            Direction::Down => vert += cmd.value,
-        }
-    }
-
-    horiz * vert
-}
-
-
-fn part2(commands: &Vec<MoveCmd>) -> i32 {
-    let mut horiz = 0;
-    let mut vert = 0;
-    let mut aim = 0;
-    for cmd in commands {
-        match cmd.dir {
-            Direction::Down => aim += cmd.value, // flipped again
-            Direction::Up => aim -= cmd.value,
-            Direction::Forward => {
-                horiz += cmd.value;
-                vert +=  cmd.value * aim;
-            }
-        }
-    }
-
-    horiz * vert
-}
-
-
-pub fn run(data: &str) -> eyre::Result<()> {
-    let mut commands = Vec::new();
-    for res in data.parse_lines::<MoveCmd>() {
-        commands.push(res?);
-    }
-
-    println!("One: {}", part1(&commands));
-    println!("Two: {}", part2(&commands));
-    Ok(())
-}

2021/src/lib.rs

@@ -36,7 +36,7 @@ pub trait ParseLines {
 }
 
 
-impl ParseLines for str {
+impl ParseLines for String {
     fn parse_lines<T: FromStr>(&self) -> LineParser<'_, T> {
         LineParser {
             it: self.lines(),
@@ -45,10 +45,3 @@ impl ParseLines for str {
     }
 }
 
-
-impl ParseLines for String {
-    fn parse_lines<T: FromStr>(&self) -> LineParser<'_, T> {
-        self[..].parse_lines::<T>()
-    }
-}
-

2021/src/main.rs

@@ -1,14 +1,45 @@
 use color_eyre::eyre;
 
 mod lib;
-use lib::load;
+use lib::{load, ParseLines};
-
-mod day2;
-
 
 
 
 fn main() -> eyre::Result<()> {
-    let data = load("data/02.txt")?;
+    day_one()
-    day2::run(&data)
 }
+
+
+fn day_one() -> eyre::Result<()> {
+    let data = load("data/01.txt")?;
+
+    let mut single_increases = 0;
+    let mut window_increases = 0;
+    let mut prev = (None, None, None);
+    for res in data.parse_lines::<i32>() {
+        let n = res?;
+        if let Some(p) = prev.2 {
+            // apparently we can't combine "if let" and regular boolean conditions
+            if n > p {
+                single_increases += 1;
+            }
+        }
+
+        if let (Some(first), Some(second), Some(third)) = prev {
+            if (n + second + third) > (first + second + third) {
+                window_increases += 1;
+            }
+        }
+        // would have forgotten this if not for the warning triggered by "let mut" without mutation
+        prev = (prev.1, prev.2, Some(n));
+    }
+
+    println!("One: {}", single_increases);
+    println!("Two: {}", window_increases);
+    Ok(())
+}
+
+
+// fn day_two() -> eyre::Result<()> {
+
+// }