d15

res/15/example

@@ -0,0 +1 @@
+rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7

src/days/d15.rs

@@ -0,0 +1,59 @@
+use std::{collections::HashMap, fs};
+
+pub fn solve() {
+    let path = "res/15/input";
+
+    let mut contents = fs::read_to_string(path).expect("I/O error, wrong path?");
+    //let contents = BufReader::new(fs::File::open(path).expect("I/O error, wrong path?"));
+
+    contents.retain(|c| !c.is_whitespace());
+    let result: usize = contents
+        .split(',')
+        .map(|p| p.chars().fold(0, |x, y| ((x + y as usize) * 17) % 256))
+        .sum();
+
+    println!("Result 1: {result}");
+
+    let mut boxes: HashMap<usize, Vec<(&str, usize)>> = HashMap::new();
+    for p in contents.split(',') {
+        let (t, n) = match p.contains('=') {
+            true => {
+                let (t, n) = p.split_once('=').unwrap();
+                (t, n.parse::<usize>().unwrap())
+            }
+            false => {
+                let (t, _) = p.split_once('-').unwrap();
+                (t, 0usize)
+            }
+        };
+        let i = t.chars().fold(0, |x, y| ((x + y as usize) * 17) % 256);
+
+        let v = boxes.entry(i).or_insert(vec![]);
+        if n == 0 {
+            if v.iter().any(|(p, _)| *p == t) {
+                v.remove(v.iter().position(|(p, _)| *p == t).unwrap());
+            }
+        } else {
+            if v.iter().any(|(p, _)| *p == t) {
+                let pos = v.iter().position(|(p, _)| *p == t).unwrap();
+                v[pos] = (t, n);
+            } else {
+                v.push((t, n))
+            }
+        }
+    }
+
+    dbg!(&boxes);
+
+    let result: usize = boxes
+        .iter()
+        .map(|(k, v)| {
+            v.iter()
+                .enumerate()
+                .map(|(i, (_, n))| (k + 1) * (i + 1) * n)
+                .sum::<usize>()
+        })
+        .sum();
+
+    println!("Result 2: {result}");
+}

src/main.rs

@@ -5,8 +5,8 @@ extern crate scan_fmt;
 use std::time::Instant;
 
 fn main() {
-    //days::d14::solve()
+    days::d15::solve()
-    _all_days()
+    //_all_days()
 }
 
 fn _all_days() {
@@ -66,6 +66,10 @@ fn _all_days() {
     println!("\nDay 14");
     days::d14::solve();
     print_elapsed(&start);
+
+    println!("\nDay 15");
+    days::d15::solve();
+    print_elapsed(&start);
 }
 
 fn print_elapsed(start: &Instant) {