Day 05

src/day05.rs

@@ -0,0 +1,77 @@
+use std::{default, collections::VecDeque};
+
+use aoc_runner_derive::{aoc, aoc_generator};
+use itertools::Itertools;
+
+#[derive(Debug)]
+pub struct Instruction {
+    from: usize,
+    to: usize,
+    num: usize,
+}
+
+#[aoc_generator(day05)]
+pub fn input_generator(input: &str) -> (Vec<Vec<char>>, Vec<Instruction>) {
+    let mut instructions = vec![];
+    let mut rows = vec![];
+    for line in input.lines() {
+        if line.trim().starts_with('[') {
+            let mut row = vec![];
+            for chunk in &line.chars().chunks(4) {
+                let boxes = chunk.filter(|c| c.is_ascii_uppercase()).collect::<Vec<char>>();
+                row.push(boxes.first().copied())
+            }
+            rows.push(row);
+        }
+        if line.starts_with("move") {
+            let mut nums: Vec<usize> = vec![];
+            for w in line.split_ascii_whitespace() {
+                if w.chars().all(|c| c.is_ascii_digit()) {
+                    nums.push(w.parse().unwrap())
+                }
+            }
+            instructions.push(Instruction {
+                num: nums[0],
+                from: nums[1]-1,
+                to: nums[2]-1,
+            })
+        }
+    }
+    let num_stacks = rows.iter().map(|v| v.len()).max().unwrap_or_default();
+    let mut stacks: Vec<Vec<char>> = vec![];
+    stacks.resize(num_stacks, Default::default());
+    for row in rows.iter().rev() {
+        for (stack,item) in row.iter().enumerate() {
+            stacks[stack].extend(item);
+        }
+    }
+    (stacks,instructions)
+}
+
+#[aoc(day05, part1)]
+pub fn solve_part1((stacks, instructions): &(Vec<Vec<char>>, Vec<Instruction>)) -> String {
+    let mut stacks = stacks.clone();
+    for inst in instructions {
+        for _ in 0..inst.num {
+            let item = stacks[inst.from].pop();
+            stacks[inst.to].extend(item);
+        }
+    }
+    stacks.iter().filter_map(|s| s.last()).collect()
+}
+
+#[aoc(day05, part2)]
+pub fn solve_part2((stacks, instructions): &(Vec<Vec<char>>, Vec<Instruction>)) -> String {
+    let mut stacks = stacks.clone();
+    let mut buffer = Vec::with_capacity(1024);
+    for inst in instructions {
+        for _ in 0..inst.num {
+            let item = stacks[inst.from].pop();
+            buffer.extend(item)
+        }
+        while let Some(item) = buffer.pop() {
+            stacks[inst.to].push(item);
+        }
+    }
+    stacks.iter().filter_map(|s| s.last()).collect()
+}

src/lib.rs

@@ -3,4 +3,5 @@ pub mod day01;
 pub mod day02;
 pub mod day03;
 pub mod day04;
+pub mod day05;
 aoc_lib! { year = 2022 }