Day 2

src/day2/mod.rs

@@ -0,0 +1,45 @@
+mod id_range;
+
+use id_range::IDRange;
+use std::{collections::HashSet, fs};
+
+fn parse_range(string: &str) -> IDRange {
+    let mut split = string.split("-");
+    let lhs = split
+        .nth(0)
+        .unwrap()
+        .parse::<u64>()
+        .expect("lhs not a digit");
+
+    let rhs = split
+        .nth(0)
+        .unwrap()
+        .parse::<u64>()
+        .expect("rhs not a digit");
+
+    IDRange::new(lhs, rhs)
+}
+
+pub fn solve_part1() {
+    let solution = solve(Some(2));
+    println!("The solution for part 1 is {}", solution);
+}
+
+pub fn solve_part2() {
+    let solution = solve(None);
+    println!("The solution for part 2 is {}", solution);
+}
+
+fn solve(limit: Option<usize>) -> u64 {
+    let file = fs::read_to_string("src/day2/input.txt").expect("You didn't provide input.txt.");
+
+    let mut invalid_ids: HashSet<u64> = HashSet::new();
+    for line in file.split(",") {
+        let range = parse_range(line);
+        for invalid in range.find_invalid_ids(limit) {
+            invalid_ids.insert(invalid);
+        }
+    }
+
+    invalid_ids.iter().sum::<u64>()
+}