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use std::io::{self, Read};
use std::u32;
fn parse_ranges(input: &str) -> Vec<(u32, u32)> {
let mut ranges = vec![];
for line in input.lines() {
let hyphen = line.find('-').unwrap();
let (start, end) = line.split_at(hyphen);
let start = start.parse().unwrap();
let end = end[1..].parse().unwrap();
ranges.push((start, end));
}
ranges.sort();
ranges
}
fn solve1(input: &str) -> u32 {
let ranges = parse_ranges(input);
let mut lowest = 0;
for &(start, end) in &ranges {
if lowest >= start && lowest <= end {
lowest = end + 1;
}
}
lowest
}
fn solve2(input: &str) -> u32 {
let ranges = parse_ranges(input);
let mut merged = vec![];
for &(start, end) in &ranges {
if let Some(&mut (ref mut last_start, ref mut last_end)) = merged.last_mut() {
if start >= *last_start && end <= *last_end {
continue;
} else if start >= *last_start && start <= *last_end + 1 && end > *last_end {
*last_end = end;
continue;
}
}
merged.push((start, end));
}
let blocked: u32 = merged.iter().map(|&(start, end)| end - start + 1).sum();
u32::MAX - blocked + 1
}
fn main() {
let mut input = String::new();
io::stdin().read_to_string(&mut input).unwrap();
println!("Part 1: {}", solve1(&input));
println!("Part 2: {}", solve2(&input));
}
#[test]
fn part1() {
let input = "
5-8
0-2
4-7
";
assert_eq!(3, solve1(input.trim()));
}
#[test]
fn part2() {
let input = "
5-8
0-2
4-7
";
assert_eq!(u32::MAX - 7, solve2(input.trim()));
}
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