Day 4

src/day04.rs

@@ -0,0 +1,45 @@
+use std::ops::RangeInclusive;
+
+use aoc_runner_derive::{aoc, aoc_generator};
+
+fn parse_range(range: &str) -> RangeInclusive<u64> {
+    let (start, end) = range.split_once('-').unwrap();
+    start.parse().unwrap()..=end.parse().unwrap()
+}
+
+#[aoc_generator(day4)]
+pub fn input_generator(input: &str) -> Vec<(RangeInclusive<u64>, RangeInclusive<u64>)> {
+    input
+        .lines()
+        .map(|l| {
+            let (first, second) = l.split_once(',').unwrap();
+            (parse_range(first), parse_range(second))
+        })
+        .collect()
+}
+
+fn contains_range(slf: &RangeInclusive<u64>, other: &RangeInclusive<u64>) -> bool {
+    slf.start() <= other.start() && slf.end() >= other.end()
+}
+
+fn overlaps_with_range(slf: &RangeInclusive<u64>, other: &RangeInclusive<u64>) -> bool {
+    slf.contains(other.start())
+}
+
+#[aoc(day4, part1)]
+pub fn solve_part1(input: &[(RangeInclusive<u64>, RangeInclusive<u64>)]) -> usize {
+    input
+        .iter()
+        .filter(|(first, second)| contains_range(first, second) | contains_range(second, first))
+        .count()
+}
+
+#[aoc(day4, part2)]
+pub fn solve_part2(input: &[(RangeInclusive<u64>, RangeInclusive<u64>)]) -> usize {
+    input
+        .iter()
+        .filter(|(first, second)| {
+            overlaps_with_range(first, second) | overlaps_with_range(second, first)
+        })
+        .count()
+}

src/lib.rs

@@ -3,5 +3,6 @@ use aoc_runner_derive::aoc_lib;
 pub mod day01;
 pub mod day02;
 pub mod day03;
+pub mod day04;
 
 aoc_lib! { year = 2022 }