do day 5

2022/src/day_5.rs

@@ -0,0 +1,82 @@
+struct Instruction {
+    count: i32,
+    start: usize,
+    end: usize,
+}
+type Data = (Vec<Vec<char>>, Vec<Instruction>);
+
+fn parse(input: &str) -> Data {
+    let (stacks, list) = input.split_once("\n\n").unwrap();
+    let mut data = vec![vec![]; 10]; // chose an arbitrary buffer size
+    let lines: Vec<&str> = stacks.lines().collect();
+    for line in lines.into_iter().rev().skip(1) {
+        let mut y = 0;
+        let mut iter = line.chars();
+        while let Some(_) = iter.next() {
+            let c = iter.next().unwrap();
+            if c != ' ' {
+                data[y].push(c);
+            }
+            iter.next();
+            iter.next();
+            y += 1;
+        }
+    }
+    let instructions = list
+        .lines()
+        .map(|item| {
+            let mut parts = item.split(' ');
+            parts.next();
+            let count = parts.next().unwrap().parse().unwrap();
+            parts.next();
+            let start = parts.next().unwrap().parse().unwrap();
+            parts.next();
+            let end = parts.next().unwrap().parse().unwrap();
+
+            Instruction { count, start, end }
+        })
+        .collect();
+    (data, instructions)
+}
+fn part_one((mut stacks, instructions): Data) -> String {
+    for i in instructions {
+        for _ in 0..i.count {
+            let item = stacks[i.start - 1].pop().unwrap();
+            stacks[i.end - 1].push(item);
+        }
+    }
+    stacks
+        .iter()
+        .filter(|s| !s.is_empty())
+        .map(|s| s[s.len() - 1])
+        .collect()
+}
+fn part_two((mut stacks, instructions): Data) -> String {
+    for i in instructions {
+        // dbg!(&stacks, &i);
+        let end_idx = stacks[i.start - 1].len() - 1;
+        let mut idx = 1 + end_idx - i.count as usize;
+        while idx <= end_idx {
+            let item = stacks[i.start - 1][idx];
+            stacks[i.end - 1].push(item);
+            idx += 1;
+        }
+        for _ in 0..i.count {
+            stacks[i.start - 1].pop();
+        }
+    }
+    stacks
+        .iter()
+        .filter(|s| !s.is_empty())
+        .map(|s| s[s.len() - 1])
+        .collect()
+}
+
+advent_of_code_macro::generate_tests!(
+    day 5,
+    parse,
+    part_one,
+    part_two,
+    sample tests ["CMZ", "MCD"],
+    star tests ["WHTLRMZRC", "GMPMLWNMG"]
+);

2022/src/lib.rs

@@ -3,3 +3,4 @@ mod day_1;
 mod day_2;
 mod day_3;
 mod day_4;
+mod day_5;