use std::fs;

fn solve_part1(ranges: &Vec<(u32, u32)>) -> u32 {
    'outer: for i in 0..u32::MAX {
        for &(lower, upper) in ranges {
            if i >= lower && i <= upper {
                // This IP is blacklisted
                continue 'outer;
            }
        }

        return i;
    }

    u32::MAX // shouldn't be reached
}

fn solve_part2(mut ranges: Vec<(u32, u32)>) -> u32 {
    // Sort by upper limit, so we know if a range is still needed
    ranges.sort_by_key(|x| x.1);

    let mut count = 0;
    'outer: for i in 0..u32::MAX {
        // Reduce the size of `ranges' to keep loop time reasonable
        if i > ranges[0].1 {
            ranges.remove(0);
        }

        for &(lower, upper) in &ranges {
            if i >= lower && i <= upper {
                // This IP is blacklisted
                continue 'outer;
            }
        }

        count += 1;
    }

    count
}

fn main() {
    // Read blacklist from input text file
    let input = fs::read_to_string("input.txt").unwrap();
    let lines: Vec<&str> = input.lines().collect();

    let mut ranges = Vec::new();
    for line in lines {
        let split: Vec<&str> = line.split('-').collect();
        let lower: u32 = split[0].parse().unwrap();
        let upper: u32 = split[1].parse().unwrap();
        ranges.push((lower, upper));
    }
    ranges.sort_by_key(|x| x.0);

    // Part 1 gives 23923783 for me
    println!("Part 1 solution: {}", solve_part1(&ranges));

    // Part 2 gives 125 for me
    println!("Part 2 solution: {}", solve_part2(ranges));
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn part1_example1() {
        let ranges = vec![(5, 8), (0, 2), (4, 7)];
        assert_eq!(solve_part1(&ranges), 3);
    }
}