From 263f2389a9dfced4d4ab76f3d42dbce53cfa77b1 Mon Sep 17 00:00:00 2001
From: Adrian Groh <adrian.groh@t-online.de>
Date: Wed, 25 Dec 2024 10:41:00 +0100
Subject: [PATCH] Add day25

---
 day25/Cargo.lock  |  7 +++++++
 day25/Cargo.toml  |  6 ++++++
 day25/src/main.rs | 49 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+)
 create mode 100644 day25/Cargo.lock
 create mode 100644 day25/Cargo.toml
 create mode 100644 day25/src/main.rs

diff --git a/day25/Cargo.lock b/day25/Cargo.lock
new file mode 100644
index 0000000..6eb9cdb
--- /dev/null
+++ b/day25/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "day25"
+version = "0.1.0"
diff --git a/day25/Cargo.toml b/day25/Cargo.toml
new file mode 100644
index 0000000..e5f4cc3
--- /dev/null
+++ b/day25/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "day25"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/day25/src/main.rs b/day25/src/main.rs
new file mode 100644
index 0000000..df158b6
--- /dev/null
+++ b/day25/src/main.rs
@@ -0,0 +1,49 @@
+#[derive(Debug, Clone)]
+struct ParsedInput {
+    keys: Vec<[u8; 5]>,
+    locks: Vec<[u8; 5]>,
+}
+
+fn parse_key(grid: &[Vec<char>]) -> [u8; 5] {
+    let mut res = [0; 5];
+    for (l_idx, line) in grid.iter().skip(1).enumerate().rev().skip(1) {
+        for (c_idx, c) in line.iter().enumerate() {
+            if c == &'#' && res[c_idx] == 0 {
+                res[c_idx] = l_idx as u8 + 1;
+            }
+        }
+    }
+    res
+}
+
+fn parse(input: &str) -> ParsedInput {
+    let mut keys = vec![];
+    let mut locks = vec![];
+    for block in input.split("\n\n") {
+        let mut grid: Vec<Vec<char>> = block.lines().map(|l| l.chars().collect()).collect();
+        if grid[0][0] == '#' {
+            locks.push(parse_key(&grid));
+        } else {
+            grid.reverse();
+            keys.push(parse_key(&grid));
+        }
+    }
+    ParsedInput { keys, locks }
+}
+
+fn overlaps(key: &[u8; 5], lock: &[u8; 5]) -> bool {
+    key.iter().zip(lock.iter()).any(|(k, l)| 5 - k < *l)
+}
+
+fn part1(parsed_input: &ParsedInput) -> usize {
+    parsed_input
+        .locks
+        .iter()
+        .map(|l| parsed_input.keys.iter().filter(|k| !overlaps(k, l)).count())
+        .sum()
+}
+
+fn main() {
+    let input = parse(include_str!("../input.txt"));
+    println!("{}", part1(&input));
+}