days 5 + 6

day05/src/main.rs

@@ -0,0 +1,75 @@
+#![feature(iter_next_chunk)]
+use std::collections::VecDeque;
+
+const OFFSET: usize = 4;
+
+enum MachineType {
+    Type9000,
+    Type9001,
+}
+
+fn main() {
+    let f = std::fs::read_to_string("/dev/stdin").unwrap();
+    let (crates, instructions) = f.split_once("\n\n").unwrap();
+    let (crates, instructions) = (crates.lines(), instructions.lines());
+
+    let mut stacks: Vec<VecDeque<&str>> =
+        vec![VecDeque::new(); (f.lines().next().unwrap().len() / 4) + 1];
+
+    for crate_str in crates {
+        for i in (1..crate_str.len()).step_by(OFFSET) {
+            if let Some(crate_label) = crate_str.get(i..i + 1) {
+                if !crate_label.chars().next().unwrap().is_alphabetic() {
+                    continue;
+                }
+                let vee = stacks.get_mut(i / 4).unwrap();
+                vee.push_front(crate_label);
+            }
+        }
+    }
+
+    let (mut reset_stacks, reset_instructions) = (stacks.clone(), instructions.clone());
+
+    solve(instructions, &mut stacks, MachineType::Type9000);
+    solve(reset_instructions, &mut reset_stacks, MachineType::Type9001);
+}
+
+fn solve(instructions: core::str::Lines, stacks: &mut [VecDeque<&str>], machine_type: MachineType) {
+    for instruction in instructions {
+        if let Ok([amount, source, dest]) = instruction
+            .split_whitespace()
+            .filter_map(|n| n.parse::<usize>().ok())
+            .next_chunk()
+        {
+            let mut temp = VecDeque::new();
+            let source_stack = stacks.get_mut(source - 1).unwrap();
+            for _ in 0..amount {
+                temp.push_front(source_stack.pop_back().unwrap());
+            }
+            let dest_stack = stacks.get_mut(dest - 1).unwrap();
+            match machine_type {
+                MachineType::Type9000 => {
+                    for _ in 0..amount {
+                        dest_stack.push_back(temp.pop_back().unwrap());
+                    }
+                }
+                MachineType::Type9001 => {
+                    if amount == 1 {
+                        dest_stack.push_back(temp.pop_back().unwrap());
+                    } else {
+                        dest_stack.append(&mut temp);
+                    }
+                }
+            }
+        }
+    }
+    if matches!(machine_type, MachineType::Type9000) {
+        print!("P1: ");
+    } else {
+        print!("P2: ");
+    }
+    for stack in stacks.iter_mut() {
+        print!("{}", stack.pop_back().unwrap());
+    }
+    println!();
+}