From b835d5cc786f284c1f1752fb01c135b267f9bb87 Mon Sep 17 00:00:00 2001 From: Justin Worthe Date: Thu, 15 Dec 2016 12:50:14 +0200 Subject: Changed input parsing to decrease number of unwraps --- aoc15/src/main.rs | 31 +++++++++++++++---------------- 1 file changed, 15 insertions(+), 16 deletions(-) (limited to 'aoc15') diff --git a/aoc15/src/main.rs b/aoc15/src/main.rs index 3db59ea..a7f0f64 100644 --- a/aoc15/src/main.rs +++ b/aoc15/src/main.rs @@ -8,29 +8,28 @@ use std::fs::File; fn main() { let gears = read_file(); - let pass = (0..).find(|&i| can_pass(&gears, i)).unwrap(); + 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)>, time: i32) -> bool { - for i in 0..gears.len() { - let (gear_pos, gear_size) = gears[i]; - if (gear_pos + time + i as i32 + 1) % gear_size != 0 { - return false; - } - } - true +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)> { +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(); + let line_regex = Regex::new(r"Disc #(\d+) has (\d+) positions; at time=0, it is at position (\d+).").unwrap(); file.lines() - .map(|line| line.unwrap().trim().to_string()) - .filter(|line| line.len() > 0) - .map(|line| { - let cap = line_regex.captures(line.as_ref()).unwrap(); - (cap.at(2).unwrap().parse().unwrap(), cap.at(1).unwrap().parse().unwrap()) + .filter_map(|line| { + line_regex.captures(line.unwrap().as_ref()).and_then(|cap| { + let time_offset = cap.at(1).and_then(|s| s.parse::().ok()); + let init_pos = cap.at(3).and_then(|s| s.parse::().ok()); + let gear_size = cap.at(2).and_then(|s| s.parse::().ok()); + match (time_offset, init_pos, gear_size) { + (Some(a), Some(b), Some(c)) => Some((a,b,c)), + _ => None + } + }) }) .collect() } -- cgit v1.2.3