Add solution for day 4
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27e5979042
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@ -2,6 +2,31 @@
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# It is not intended for manual editing.
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version = 3
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[[package]]
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name = "memchr"
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version = "2.5.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
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[[package]]
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name = "minimal-lexical"
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version = "0.2.1"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
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[[package]]
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name = "nom"
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version = "7.1.1"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "a8903e5a29a317527874d0402f867152a3d21c908bb0b933e416c65e301d4c36"
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dependencies = [
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"memchr",
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"minimal-lexical",
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]
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[[package]]
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name = "problems"
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version = "0.1.0"
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dependencies = [
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"nom",
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]
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@ -6,3 +6,4 @@ edition = "2021"
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# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
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[dependencies]
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nom = { version = "7" }
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File diff suppressed because it is too large
Load Diff
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@ -0,0 +1,150 @@
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use nom::{self, bytes::complete::tag, character::complete, sequence::separated_pair, IResult};
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use std::collections::HashSet;
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const INPUT: &str = include_str!("../data/day4.txt");
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pub fn part1() -> String {
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format!("{}", count_full_containments(input(INPUT)))
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}
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pub fn part2() -> String {
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format!("{}", count_overlaps(input(INPUT)))
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}
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fn count_full_containments(pairings: Vec<ElfPairing>) -> u32 {
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pairings.into_iter().fold(0, |cur, pairing| {
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if pairing.has_full_containment() {
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cur + 1
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} else {
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cur
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}
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})
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}
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fn count_overlaps(pairings: Vec<ElfPairing>) -> u32 {
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pairings.into_iter().fold(
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0,
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|cur, pairing| {
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if pairing.has_overlap() {
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cur + 1
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} else {
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cur
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}
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},
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)
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}
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struct ElfPairing {
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elf1: Vec<u32>,
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elf2: Vec<u32>,
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}
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impl ElfPairing {
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fn has_full_containment(&self) -> bool {
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let elf1 = self.elf1.iter().cloned().collect::<HashSet<u32>>();
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let elf2 = self.elf2.iter().cloned().collect::<HashSet<u32>>();
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elf1.is_subset(&elf2) || elf2.is_subset(&elf1)
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}
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fn has_overlap(&self) -> bool {
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let element_count = self.elf1.len() + self.elf2.len();
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let combined_set = self
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.elf1
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.iter()
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.chain(self.elf2.iter())
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.cloned()
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.collect::<HashSet<u32>>();
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combined_set.len() < element_count
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}
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}
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fn input(data: &str) -> Vec<ElfPairing> {
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data.lines()
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.map(|line| {
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let (_, pairing) = elf_pair(line).unwrap();
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pairing
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})
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.collect::<Vec<ElfPairing>>()
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}
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fn elf_pair(input: &str) -> IResult<&str, ElfPairing> {
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let (input, elf1) = elf_range(input)?;
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let (input, _) = tag(",")(input)?;
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let (input, elf2) = elf_range(input)?;
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Ok((input, ElfPairing { elf1, elf2 }))
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}
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fn elf_range(input: &str) -> IResult<&str, Vec<u32>> {
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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 + 1).collect::<Vec<u32>>()))
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}
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#[cfg(test)]
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mod test {
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use super::*;
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const TEST_DATA: &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 it_gets_a_hashset_from_a_range() {
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assert_eq!(vec![2, 3, 4], (2..5).collect::<Vec<u32>>());
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}
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fn with_input<F>(test: F)
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where
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F: Fn(Vec<ElfPairing>) -> () + std::panic::UnwindSafe,
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{
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test(input(TEST_DATA));
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}
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#[test]
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fn it_parses_input_correctly() {
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with_input(|pairings| {
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assert_eq!(vec![2, 3, 4], pairings[0].elf1);
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assert_eq!(vec![6, 7, 8], pairings[0].elf2);
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assert_eq!(vec![6], pairings[4].elf1);
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assert_eq!(vec![4, 5, 6], pairings[4].elf2);
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});
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}
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#[test]
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fn it_checks_full_containment() {
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with_input(|pairings| {
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assert!(!pairings[0].has_full_containment());
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assert!(!pairings[1].has_full_containment());
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assert!(!pairings[2].has_full_containment());
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assert!(pairings[3].has_full_containment());
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assert!(pairings[4].has_full_containment());
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assert!(!pairings[5].has_full_containment());
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});
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}
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#[test]
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fn it_counts_full_containments() {
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with_input(|pairings| {
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assert_eq!(2, count_full_containments(pairings));
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});
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}
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#[test]
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fn it_checks_overlap() {
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with_input(|pairings| {
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assert!(!pairings[0].has_overlap());
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assert!(!pairings[1].has_overlap());
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assert!(pairings[2].has_overlap());
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assert!(pairings[3].has_overlap());
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assert!(pairings[4].has_overlap());
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assert!(pairings[5].has_overlap());
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});
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}
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}
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@ -1,6 +1,7 @@
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mod day1;
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mod day2;
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mod day3;
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mod day4;
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fn main() {
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let day = std::env::args().skip(1).next();
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@ -12,6 +13,8 @@ fn main() {
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Some("2b") => day2::part2(),
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Some("3a") => day3::part1(),
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Some("3b") => day3::part2(),
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Some("4a") => day4::part1(),
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Some("4b") => day4::part2(),
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_ => panic!("unrecognized day"),
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};
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