day 4. cruisin

day4/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day4"
+version = "0.1.0"

day4/Cargo.toml

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+[package]
+name = "day4"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day4/src/main.rs

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+#[derive(Debug)]
+struct Assignment {
+    left: (u32, u32),
+    right: (u32, u32),
+}
+
+fn main() {
+    let contents = std::fs::read_to_string("data.txt").expect("Failed to read file");
+    let lines: Vec<&str> = contents.lines().collect();
+    let assignments: Vec<Assignment> = lines.iter().map(|x| parse_line(&x)).collect();
+
+    // Part 1
+    let num_contained: usize = assignments
+        .iter()
+        .map(|a| any_fully_contained(&a))
+        .filter(|&x| x)
+        .collect::<Vec<bool>>()
+        .len();
+    println!("Number fully contained: {:?}", num_contained);
+
+    // Part 2
+    let num_overlap: usize = assignments
+        .iter()
+        .map(|a| any_overlap(&a))
+        .filter(|&x| x)
+        .collect::<Vec<bool>>()
+        .len();
+    println!("Number overlapping: {:?}", num_overlap);
+}
+
+fn parse_line(l: &str) -> Assignment {
+    let parts: Vec<&str> = l.split(',').collect();
+    let pairs: Vec<Vec<&str>> = parts.iter().map(|x| x.split('-').collect()).collect();
+    let pairs: Vec<Vec<u32>> = pairs // map to u32
+        .iter()
+        .map(|x| x.iter().map(|y| y.parse().unwrap()).collect())
+        .collect();
+
+    Assignment {
+        left: (pairs[0][0], pairs[0][1]),
+        right: (pairs[1][0], pairs[1][1]),
+    }
+}
+
+fn any_fully_contained(a: &Assignment) -> bool {
+    (a.left.0 <= a.right.0 && a.left.1 >= a.right.1) || // left fully contains right
+    (a.right.0 <= a.left.0 && a.right.1 >= a.left.1) // or right fully contains left
+}
+
+fn any_overlap(a: &Assignment) -> bool {
+    (a.left.0 >= a.right.0 && a.left.0 <= a.right.1)
+        || (a.left.1 >= a.right.0 && a.left.1 <= a.right.1)
+        || (a.right.0 >= a.left.0 && a.right.0 <= a.left.1)
+        || (a.right.1 >= a.left.0 && a.right.1 <= a.left.1)
+}

day4/test.txt

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+2-4,6-8
+2-3,4-5
+5-7,7-9
+2-8,3-7
+6-6,4-6
+2-6,4-8