75 lines
1.8 KiB
Rust
75 lines
1.8 KiB
Rust
use nom::IResult;
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use std::ops::RangeInclusive;
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pub fn process_part_1(input: &str) -> usize {
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let (_, assignments) = section_assignments(input).unwrap();
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assignments
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.iter()
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.filter(|(a, b)| range_contains(a, b) || range_contains(b, a))
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.count()
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}
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pub fn process_part_2(input: &str) -> usize {
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let (_, assignments) = section_assignments(input).unwrap();
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assignments
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.iter()
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.filter(|(a, b)| a.clone().into_iter().any(|n| b.contains(&n)))
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.count()
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}
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fn range_contains(haystack: &RangeInclusive<u32>, needle: &RangeInclusive<u32>) -> bool {
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haystack.contains(needle.start()) && haystack.contains(needle.end())
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}
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fn section_assignments(
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input: &str,
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) -> IResult<&str, Vec<(RangeInclusive<u32>, RangeInclusive<u32>)>> {
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use nom::character::complete::newline;
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use nom::multi::separated_list1;
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let (input, ranges) = separated_list1(newline, line)(input)?;
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Ok((input, ranges))
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}
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fn line(input: &str) -> IResult<&str, (RangeInclusive<u32>, RangeInclusive<u32>)> {
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use nom::bytes::complete::tag;
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let (input, start) = sections(input)?;
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let (input, _) = tag(",")(input)?;
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let (input, end) = sections(input)?;
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Ok((input, (start, end)))
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}
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fn sections(input: &str) -> IResult<&str, RangeInclusive<u32>> {
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use nom::bytes::complete::tag;
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use nom::character::complete;
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let (input, start) = complete::u32(input)?;
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let (input, _) = tag("-")(input)?;
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let (input, end) = complete::u32(input)?;
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Ok((input, start..=end))
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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const INPUT: &str = "2-4,6-8
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2-3,4-5
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5-7,7-9
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2-8,3-7
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6-6,4-6
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2-6,4-8";
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#[test]
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fn day1() {
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assert_eq!(process_part_1(INPUT), 2);
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}
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#[test]
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fn day2() {
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assert_eq!(process_part_2(INPUT), 4);
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}
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}
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