1 files changed, 35 insertions, 0 deletions
diff --git a/2016/aoc15/src/main.rs b/2016/aoc15/src/main.rs
new file mode 100644
index 0000000..a7f0f64
--- /dev/null
+++ b/2016/aoc15/src/main.rs
@@ -0,0 +1,35 @@
+extern crate regex;
+
+use regex::Regex;
+use std::io::BufReader;
+use std::io::prelude::*;
+use std::fs::File;
+
+
+fn main() {
+    let gears = read_file();
+    let pass = (0..).find(|&i| can_pass(&gears, i)).expect("Reached end of infinite range without finding output");
+    println!("First pass at t={}", pass);
+}
+
+fn can_pass(gears: &Vec<(i32, i32, i32)>, time: i32) -> bool {
+    gears.iter().all(|&(time_offset, init_pos, gear_size)| (init_pos + time_offset + time) % gear_size == 0)
+}
+
+fn read_file() -> Vec<(i32, i32, i32)> {
+    let file = BufReader::new(File::open("input.txt").unwrap());
+    let line_regex = Regex::new(r"Disc #(\d+) has (\d+) positions; at time=0, it is at position (\d+).").unwrap();
+    file.lines()
+        .filter_map(|line| {
+            line_regex.captures(line.unwrap().as_ref()).and_then(|cap| {
+                let time_offset = cap.at(1).and_then(|s| s.parse::<i32>().ok());
+                let init_pos = cap.at(3).and_then(|s| s.parse::<i32>().ok());
+                let gear_size = cap.at(2).and_then(|s| s.parse::<i32>().ok());
+                match (time_offset, init_pos, gear_size) {
+                    (Some(a), Some(b), Some(c)) => Some((a,b,c)),
+                    _ => None
+                }
+            })
+        })
+        .collect()
+}