Day Five

1 files changed, 54 insertions, 0 deletions

diff --git a/2022/rust/day05/src/main.rs b/2022/rust/day05/src/main.rs
new file mode 100644
index 0000000..b13d16e
--- /dev/null
+++ b/2022/rust/day05/src/main.rs
@@ -0,0 +1,54 @@
+use std::collections::VecDeque;
+use std::env;
+use std::fs;
+use text_io::scan;
+
+fn main() {
+    let args = env::args().nth(1).expect("missing input");
+    let input = fs::read_to_string(args).unwrap();
+    let mut parts = input.split("\n\n");
+
+    let crates = parts.next().unwrap();
+    // yes, it's gross. yes, it works. no, i couldn't think of anything better.
+    let mut stacks: Vec<Vec<char>> = vec![];
+    for i in 0..9 {
+        let mut stack: Vec<char> = vec![];
+        for j in 0..8 {
+            stack.push(crates.chars().nth((9*4) * (7-j) + 4*i + 1).unwrap());
+        }
+        while *stack.last().unwrap() == ' ' {
+            stack.pop();
+        }
+        stacks.push(stack);
+    }
+
+    let instructions: Vec<[usize; 3]> = parts.next().unwrap().trim().split("\n").map(|x| {
+        let a: usize;
+        let b: usize;
+        let c: usize;
+        scan!(x.bytes() => "move {} from {} to {}", a, b, c);
+        return [a, b, c];
+    }).collect(); // collect() still messes me up
+    let capacity: usize = instructions.iter().fold(0, |x,y| x.max(y[0]));
+
+    let mut stack = stacks.clone();
+    for ins in &instructions {
+        for _ in 0 .. ins[0] {
+            let cargo = stack[ins[1]-1].pop().unwrap();
+            stack[ins[2]-1].push(cargo);
+        }
+    }
+    let answer: String = stack.iter().map(|x| x.last().unwrap()).collect();
+    println!("{}", answer);
+
+    let mut stack = stacks.clone();
+    for ins in instructions {
+        let mut cargo: VecDeque<char> = VecDeque::with_capacity(capacity);
+        for _ in 0 .. ins[0] {
+            cargo.push_front(stack[ins[1]-1].pop().unwrap());
+        }
+        stack[ins[2]-1].append(&mut cargo.into());
+    }
+    let answer: String = stack.iter().map(|x| x.last().unwrap()).collect();
+    println!("{}", answer);
+}