Files
AoC-2025/src/5-cafeteria.rs
James Hogge b1dc693fbf Days 1-5
2025-12-09 04:18:46 +00:00

49 lines
1.3 KiB
Rust

use std::{cmp::max, fs::File, io::{self, BufRead, BufReader}};
fn parse_range(s: &str) -> (u64, u64) {
let (s1, s2) = s.split_once('-').unwrap();
(s1.parse().unwrap(), s2.parse().unwrap())
}
fn main() -> Result<(), io::Error> {
let f = File::open("5-input.txt")?;
let reader = BufReader::new(f);
let mut lines = reader.lines().map_while(Result::ok);
let mut ranges: Vec<_> = lines
.by_ref()
.take_while(|l| !l.is_empty())
.map(|l| parse_range(&l))
.collect();
ranges.sort_unstable();
let mut ids: Vec<u64> = lines
.map(|l| l.parse::<u64>().unwrap())
.collect();
ids.sort_unstable();
let mut total = 0;
// let mut range_idx = 0;
// let mut id_idx = 0;
// while id_idx < ids.len() && range_idx < ranges.len() {
// let (low, high) = ranges[range_idx];
// if ids[id_idx] < low {
// id_idx += 1;
// } else if ids[id_idx] <= high {
// id_idx += 1;
// total += 1;
// } else {
// range_idx += 1;
// }
// }
let mut max_seen = 0;
for (low, high) in ranges {
let new_low = max(low, max_seen + 1);
max_seen = max(high, max_seen);
total += 1 + max_seen - new_low;
}
println!("Result {}", total);
Ok(())
}