day 4

day4/Cargo.toml

@@ -0,0 +1,8 @@
+[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/sample_input.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

day4/src/main.rs

@@ -0,0 +1,34 @@
+use std::{collections::HashSet, cmp::min};
+
+fn main() {
+    const INPUT: &str = include_str!("../input.txt");
+    let input = INPUT.lines();
+
+    let mut count_complete: u64 = 0;
+    let mut count_partial: u64 = 0;
+    for line in input {
+        let (first, second) = line.split_once(',').unwrap();
+
+        let first: (&str, &str) = first.split_once('-').unwrap();
+        let first: (u64, u64) = (first.0.parse::<u64>().unwrap(), first.1.parse::<u64>().unwrap());
+
+        let second: (&str, &str) = second.split_once('-').unwrap();
+        let second: (u64, u64) = (second.0.parse::<u64>().unwrap(), second.1.parse::<u64>().unwrap());
+
+        let first_set: HashSet<u64> = HashSet::from_iter(first.0..=first.1);
+        let second_set: HashSet<u64> = HashSet::from_iter(second.0..=second.1);
+
+        let smallest_len = min(first_set.len(), second_set.len());
+        let intersection_len = first_set.intersection(&second_set).count();
+
+        if intersection_len == smallest_len {
+            count_complete += 1;
+        }
+
+        if intersection_len > 0 {
+            count_partial += 1;
+        }
+    }
+
+    println!("Partial: {count_partial}, Complete: {count_complete}");
+}