From ff8b8dac0c0d9d01321441237e1d0b3d6fc6f38f Mon Sep 17 00:00:00 2001
From: Bert Peters <bert@bertptrs.nl>
Date: Wed, 10 Dec 2025 08:39:51 +0100
Subject: [PATCH] 2025 day 10 part 1 in Rust

---
 2025/day10/.gitignore  |   1 +
 2025/day10/Cargo.toml  |   6 +++
 2025/day10/sample.txt  |   3 ++
 2025/day10/src/main.rs | 103 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 113 insertions(+)
 create mode 100644 2025/day10/.gitignore
 create mode 100644 2025/day10/Cargo.toml
 create mode 100644 2025/day10/sample.txt
 create mode 100644 2025/day10/src/main.rs

diff --git a/2025/day10/.gitignore b/2025/day10/.gitignore
new file mode 100644
index 0000000..2f7896d
--- /dev/null
+++ b/2025/day10/.gitignore
@@ -0,0 +1 @@
+target/
diff --git a/2025/day10/Cargo.toml b/2025/day10/Cargo.toml
new file mode 100644
index 0000000..8902ce5
--- /dev/null
+++ b/2025/day10/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "solve"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/2025/day10/sample.txt b/2025/day10/sample.txt
new file mode 100644
index 0000000..dd91d7b
--- /dev/null
+++ b/2025/day10/sample.txt
@@ -0,0 +1,3 @@
+[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}
+[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
+[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}
diff --git a/2025/day10/src/main.rs b/2025/day10/src/main.rs
new file mode 100644
index 0000000..8ac062d
--- /dev/null
+++ b/2025/day10/src/main.rs
@@ -0,0 +1,103 @@
+use std::collections::VecDeque;
+use std::env;
+use std::fs;
+use std::io;
+
+fn parse_line(line: &str) -> (u32, Vec<u32>) {
+    let mut buttons = vec![];
+    let mut target = 0;
+
+    let mut it = line.chars();
+
+    for (i, c) in it.by_ref().skip(1).enumerate() {
+        match c {
+            '#' => target |= 1 << i,
+            '.' => (),
+            _ => break,
+        }
+    }
+
+    loop {
+        match it.nth(1) {
+            Some('{') => break,
+            Some('(') => (),
+            other => panic!("Unexpected character \"{other:?}\" in: {line}"),
+        }
+
+        let mut button = 0;
+
+        while let Some(c) = it.next() {
+            let d = c.to_digit(10).unwrap();
+            button |= 1 << d;
+
+            if let Some(')') = it.next() {
+                break;
+            }
+        }
+
+        buttons.push(button);
+    }
+
+    (target, buttons)
+}
+
+fn minimum_clicks(target: u32, buttons: &[u32]) -> i32 {
+    let max = buttons
+        .iter()
+        .map(|s| 32 - s.leading_zeros())
+        .max()
+        .unwrap_or(0);
+    let possible = 2 << max;
+    let mut seen = vec![false; possible];
+    let mut todo = VecDeque::new();
+    todo.push_back((0, 0));
+
+    while let Some((steps, state)) = todo.pop_front() {
+        for &button in buttons {
+            let next = state ^ button;
+
+            if next == target {
+                return steps + 1;
+            } else if !seen[next as usize] {
+                seen[next as usize] = true;
+                todo.push_back((steps + 1, next));
+            }
+        }
+    }
+
+    unreachable!("Did not find target");
+}
+
+fn solve(input: &str) -> i32 {
+    let mut total_clicks = 0;
+    for line in input.trim().lines() {
+        let (target, buttons) = parse_line(line);
+        total_clicks += minimum_clicks(target, &buttons);
+    }
+
+    total_clicks
+}
+
+fn main() -> io::Result<()> {
+    if let Some(path) = env::args_os().nth(1) {
+        let input = fs::read_to_string(path)?;
+
+        println!("{}", solve(&input));
+        Ok(())
+    } else {
+        eprintln!("Usage: {} INPUT_FILE", env::args().next().unwrap());
+        std::process::exit(1);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    const SAMPLE: &str = include_str!("../sample.txt");
+
+    #[test]
+    fn test_part1() {
+        assert_eq!(7, solve(SAMPLE));
+    }
+}