feat: day 4 (12:04.60)

src/bin/day_4.rs

@@ -0,0 +1,78 @@
+use std::ops::RangeInclusive;
+
+use aoc_2022::prelude::*;
+
+type Input = Vec<(RangeInclusive<usize>, RangeInclusive<usize>)>;
+
+fn parse_range(s: &str) -> RangeInclusive<usize> {
+    let (lower, upper) = s.split_once("-").expect("range to have dash");
+    let (lower, upper) = (lower.parse::<usize>().expect("valid number"), upper.parse::<usize>().expect("valid number"));
+    lower..=upper
+}
+
+fn parse(s: &str) -> Result<Input> {
+    Ok(s.lines().map(|line| {
+        let (a, b) = line.split_once(",").expect("comma in line");
+        (parse_range(a), parse_range(b))
+    }).collect::<Vec<_>>())
+}
+
+#[aoc(day = 4, parse = parse, test_cases = ["day_4.txt"])]
+fn day_4(input: Input) -> Result<()> {
+    // Part 1
+    let mut fully_contained = 0;
+    for (a, b) in &input {
+        let mut overlaps = true;
+        for v in a.clone() {
+            if !b.contains(&v) {
+                overlaps = false;
+                break;
+            }
+        }
+        if overlaps {
+            fully_contained += 1;
+            continue;
+        }
+        overlaps = true;
+        for v in b.clone() {
+            if !a.contains(&v) {
+                overlaps = false;
+                break;
+            }
+        }
+        if overlaps {
+            fully_contained += 1;
+        }
+    }
+
+    println!("Part one: {fully_contained} pairs contain themselves!");
+
+    // Part 2
+    let mut overlapping = 0;
+    for (a, b) in &input {
+        let mut overlapped = false;
+        for v in a.clone() {
+            if b.contains(&v) {
+                overlapped = true;
+                break;
+            }
+        }
+        if overlapped {
+            overlapping += 1;
+            continue;
+        }
+        for v in b.clone() {
+            if a.contains(&v) {
+                overlapped = true;
+                break;
+            }
+        }
+        if overlapped {
+            overlapping += 1;
+        }
+    }
+
+    println!("Part two: {overlapping} pairs overlap in any way");
+
+    Ok(())
+}

test_cases/day_4.txt

@@ -0,0 +1,6 @@
+2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8