day5

src/day5.rs

@@ -0,0 +1,163 @@
+use std::collections::{HashMap, VecDeque};
+use std::fmt::format;
+use std::fs;
+
+use itertools::Itertools;
+
+pub fn run() {
+    println!("Day 5:");
+    let input = fs::read_to_string("./inputs/day5.txt").expect("Could not read file");
+
+    println!("\tPart 1: {}", part1(&input));
+    println!("\tPart 2: {}", part2(&input));
+}
+
+#[derive(Debug)]
+struct Command {
+    amount: usize,
+    from: usize,
+    to: usize,
+}
+
+fn part1(input: &str) -> String {
+    let (stack_input, moves_input) = input.split_once("\n\n").unwrap();
+
+    let mut containers: HashMap<usize, VecDeque<char>> = HashMap::new();
+    for row in stack_input.lines() {
+        for (column, (lbracket, container, _rbracket, _)) in
+            format!("{} ", row).chars().tuples().enumerate()
+        {
+            if lbracket == '[' && !container.is_whitespace() {
+                containers
+                    .entry(column + 1)
+                    .or_insert_with(VecDeque::new)
+                    .push_back(container);
+            }
+        }
+    }
+
+    let commands = moves_input.lines().map(|line| {
+        let (amount, from, to) =
+            scan_fmt!(line, "move {} from {} to {}", usize, usize, usize).unwrap();
+        Command { amount, from, to }
+    });
+
+    for command in commands {
+        for _ in 0..command.amount {
+            let container = containers
+                .entry(command.from)
+                .or_insert_with(VecDeque::new)
+                .pop_front()
+                .unwrap_or(' ');
+
+            if container != ' ' {
+                containers
+                    .entry(command.to)
+                    .or_insert_with(VecDeque::new)
+                    .push_front(container)
+            }
+        }
+    }
+
+    let mut answer = "".to_string();
+    for column in 1..=containers.len() {
+        answer = format!(
+            "{}{}",
+            answer,
+            containers.get(&column).unwrap().front().unwrap()
+        );
+    }
+    answer
+}
+
+fn part2(input: &str) -> String {
+    let (stack_input, moves_input) = input.split_once("\n\n").unwrap();
+
+    let mut containers: HashMap<usize, VecDeque<char>> = HashMap::new();
+    for row in stack_input.lines() {
+        for (column, (lbracket, container, _rbracket, _)) in
+            format!("{} ", row).chars().tuples().enumerate()
+        {
+            if lbracket == '[' && !container.is_whitespace() {
+                containers
+                    .entry(column + 1)
+                    .or_insert_with(VecDeque::new)
+                    .push_back(container);
+            }
+        }
+    }
+
+    let commands = moves_input.lines().map(|line| {
+        let (amount, from, to) =
+            scan_fmt!(line, "move {} from {} to {}", usize, usize, usize).unwrap();
+        Command { amount, from, to }
+    });
+
+    let mut crane = VecDeque::new();
+
+    for command in commands {
+        for _ in 0..command.amount {
+            let container = containers
+                .entry(command.from)
+                .or_insert_with(VecDeque::new)
+                .pop_front()
+                .unwrap_or(' ');
+
+            crane.push_back(container);
+        }
+        for _ in 0..command.amount {
+            let container = crane.pop_back().unwrap();
+            if container != ' ' {
+                containers
+                    .entry(command.to)
+                    .or_insert_with(VecDeque::new)
+                    .push_front(container)
+            }
+        }
+    }
+
+    let mut answer = "".to_string();
+    for column in 1..=containers.len() {
+        answer = format!(
+            "{}{}",
+            answer,
+            containers.get(&column).unwrap().front().unwrap()
+        );
+    }
+    answer
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1() {
+        let input = "    [D]    
+[N] [C]    
+[Z] [M] [P]
+ 1   2   3 
+
+move 1 from 2 to 1
+move 3 from 1 to 3
+move 2 from 2 to 1
+move 1 from 1 to 2";
+
+        assert_eq!(part1(input), "CMZ");
+    }
+
+    #[test]
+    fn test_2() {
+        let input = "    [D]    
+[N] [C]    
+[Z] [M] [P]
+ 1   2   3 
+
+move 1 from 2 to 1
+move 3 from 1 to 3
+move 2 from 2 to 1
+move 1 from 1 to 2";
+
+        assert_eq!(part2(input), "MCD");
+    }
+}

src/main.rs

@@ -1,11 +1,16 @@
+#[macro_use]
+extern crate scan_fmt;
+
 mod day1;
 mod day2;
 mod day3;
 mod day4;
+mod day5;
 fn main() {
     println!("Running Advent of Code 2022");
     day1::run();
     day2::run();
     day3::run();
     day4::run();
+    day5::run();
 }