[rs] Solve 2022_05 part 1

rs/src/y2022/d05.rs

@@ -0,0 +1,48 @@
+fn parse_stack_line(line: &str, stacks: &mut Vec<Vec<char>>) {
+    let len = (line.len() + 1) / 4;
+    while stacks.len() < len {
+        stacks.push(vec![]);
+    }
+    let line = line.chars().collect::<Vec<_>>();
+    for (i, chunk) in line[..].chunks(4).enumerate() {
+        if chunk[0] == '[' {
+            stacks[i].push(chunk[1]);
+        }
+    }
+}
+
+pub fn solve(input: String) {
+    // Parse stacks
+    let mut stacks = vec![];
+    let mut lines = input.lines();
+    for line in &mut lines {
+        if line.is_empty() {
+            break;
+        }
+        parse_stack_line(line, &mut stacks);
+    }
+    for stack in &mut stacks {
+        stack.reverse();
+    }
+
+    // Parse moves
+    let mut moves: Vec<(usize, usize, usize)> = vec![];
+    for line in lines {
+        let parts = line.split_ascii_whitespace().collect::<Vec<_>>();
+        let amount = parts[1].parse().unwrap();
+        let from = parts[3].parse().unwrap();
+        let to = parts[5].parse().unwrap();
+        moves.push((amount, from, to));
+    }
+
+    // Part 1
+    let mut part1 = stacks.clone();
+    for (amount, from, to) in moves {
+        for _ in 0..amount {
+            let value = part1[from - 1].pop().unwrap();
+            part1[to - 1].push(value);
+        }
+    }
+    let part1 = part1.iter().map(|s| s.last().unwrap()).collect::<String>();
+    println!("Part 1: {}", part1);
+}