Day 05 Part 1

src/day05/mod.rs

@@ -1,14 +1,52 @@
 use crate::read;
-use tuple_map::*;
 
 pub fn run() {
     let input = read("05");
 
-    let lines = input.lines().map(|l| l).collect::<Vec<_>>();
+    let lines = input.split_once("\n\n").unwrap();
+    let stackslines = lines.0.lines().collect::<Vec<_>>();
+    let mut stacks = std::collections::HashMap::new();
+    for l in stackslines {
+        let length = l.len();
+        let mut idx = 0;
+        while idx <= length {
+            let charnum = 1 + idx * 4;
+            if let Some(s1) = l.chars().nth(charnum) {
+                if !s1.is_whitespace() && !s1.is_numeric() {
+                    let e = stacks.entry(idx + 1).or_insert(vec![]);
+                    e.push(s1);
+                }
+            }
+            idx += 1;
+        }
+    }
+    let k = stacks.keys().max().unwrap();
+    for i in 1..=*k {
+        stacks.entry(i).and_modify(|s| s.reverse());
+    }
+
+    let re = regex::Regex::new(r"move (\d+) from (\d+) to (\d+)").unwrap();
+    for l in lines.1.lines().filter(|l| !l.is_empty()) {
+        let capt = re.captures(l).unwrap();
+        let count: usize = capt[1].parse().unwrap();
+        let from: usize = capt[2].parse().unwrap();
+        let to: usize = capt[3].parse().unwrap();
+        for _i in 0..count {
+            let fr = stacks.get_mut(&from).unwrap();
+            let c = fr.pop().unwrap();
+            stacks.entry(to).and_modify(|s| s.push(c));
+        }
+    }
+
     #[cfg(feature = "part1")]
     {
-        let count = lines.iter().count();
+        let mut keys = stacks.keys().copied().collect::<Vec<_>>();
-        println!("Day 5, Part 01: {}", count);
+        keys.sort();
+        let chars = keys
+            .iter()
+            .map(|s| stacks.get(s).unwrap().last().unwrap())
+            .collect::<String>();
+        println!("Day 5, Part 01: {}", chars);
     }
 
     #[cfg(feature = "part2")]

src/main.rs

@@ -23,7 +23,7 @@ fn main() {
         day04::run();
     }
     if cfg!(feature = "day05") || (cfg!(feature = "today") && today == 5) {
-        day04::run();
+        day05::run();
     }
     println!("Finished, time taken: {:?}", now.elapsed())
 }