From 01b077fc5f0511c4a56fe07b91f90731673cfa6d Mon Sep 17 00:00:00 2001
From: Joe Ardent <code@ardent.nebcorp.com>
Date: Fri, 3 Jan 2025 11:18:34 -0800
Subject: [PATCH] day9, part1
---
Cargo.lock | 4 +++
Cargo.toml | 2 +-
day09/Cargo.toml | 6 ++++
day09/src/main.rs | 82 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 93 insertions(+), 1 deletion(-)
create mode 100644 day09/Cargo.toml
create mode 100644 day09/src/main.rs
diff --git a/Cargo.lock b/Cargo.lock
index 1f4e226..863a1ad 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -52,6 +52,10 @@ dependencies = [
"winnow",
]
+[[package]]
+name = "day09"
+version = "0.1.0"
+
[[package]]
name = "memchr"
version = "2.7.4"
diff --git a/Cargo.toml b/Cargo.toml
index d7d46a8..e2c7c6d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
[workspace]
resolver = "2"
-members = ["day01", "day02", "day03", "day04", "day05", "day06", "day07", "day08"]
+members = ["day01", "day02", "day03", "day04", "day05", "day06", "day07", "day08", "day09"]
[workspace.dependencies]
winnow = "0.6"
diff --git a/day09/Cargo.toml b/day09/Cargo.toml
new file mode 100644
index 0000000..0ede72d
--- /dev/null
+++ b/day09/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "day09"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/day09/src/main.rs b/day09/src/main.rs
new file mode 100644
index 0000000..b898ef3
--- /dev/null
+++ b/day09/src/main.rs
@@ -0,0 +1,82 @@
+fn main() {
+ let input = std::fs::read_to_string("input").unwrap();
+ println!("{}", pt1(&input));
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Cell {
+ Free,
+ Block(usize),
+}
+
+fn pt1(input: &str) -> usize {
+ let mut next_id = 0;
+ let mut map = Vec::new();
+ let mut frees = Vec::new();
+ for (i, c) in input.chars().enumerate() {
+ let n = match c.to_digit(10) {
+ Some(n) => n as usize,
+ _ => {
+ continue;
+ }
+ };
+ if i % 2 == 0 {
+ let cell = Cell::Block(next_id);
+ for _ in 0..n {
+ map.push(cell);
+ }
+ next_id += 1;
+ } else {
+ for _ in 0..n {
+ frees.push(map.len());
+ map.push(Cell::Free);
+ }
+ }
+ }
+ let omap = map.clone();
+ let mut next_free = 0;
+ for (i, &b) in omap.iter().enumerate().rev() {
+ if b == Cell::Free {
+ continue;
+ }
+ let free = frees[next_free];
+ if i <= free {
+ break;
+ }
+ next_free += 1;
+ map.swap(free, i);
+ }
+
+ //println!("{map:?}");
+
+ map.iter()
+ .enumerate()
+ .map(|(i, &b)| match b {
+ Cell::Block(v) => i * v,
+ _ => 0,
+ })
+ .sum()
+}
+
+enum Block {
+ Free(usize),
+ // size, id
+ Block(usize, usize),
+}
+
+fn pt2(input: &str) -> usize {
+ todo!()
+}
+
+#[cfg(test)]
+mod test {
+ use super::*;
+
+ static INPUT: &str = "2333133121414131402";
+
+ #[test]
+ fn p1() {
+ let v = pt1(INPUT);
+ assert_eq!(v, 1928);
+ }
+}