Days 1-5

src/5-cafeteria.rs

@@ -0,0 +1,49 @@
+use std::{cmp::max, fs::File, io::{self, BufRead, BufReader}};
+
+fn parse_range(s: &str) -> (u64, u64) {
+    let (s1, s2) = s.split_once('-').unwrap();
+    (s1.parse().unwrap(), s2.parse().unwrap())
+}
+
+fn main() -> Result<(), io::Error> {
+    let f = File::open("5-input.txt")?;
+    let reader = BufReader::new(f);
+    let mut lines = reader.lines().map_while(Result::ok);
+
+    let mut ranges: Vec<_> = lines
+        .by_ref()
+        .take_while(|l| !l.is_empty())
+        .map(|l| parse_range(&l))
+        .collect();
+    ranges.sort_unstable();
+
+    let mut ids: Vec<u64> = lines
+        .map(|l| l.parse::<u64>().unwrap())
+        .collect();
+    ids.sort_unstable();
+
+    let mut total = 0;
+
+    // let mut range_idx = 0;
+    // let mut id_idx = 0;
+    // while id_idx < ids.len() && range_idx < ranges.len() {
+    //     let (low, high) = ranges[range_idx];
+    //     if ids[id_idx] < low {
+    //         id_idx += 1;
+    //     } else if ids[id_idx] <= high {
+    //         id_idx += 1;
+    //         total += 1;
+    //     } else {
+    //         range_idx += 1;
+    //     }
+    // }
+    
+    let mut max_seen = 0;
+    for (low, high) in ranges {
+        let new_low = max(low, max_seen + 1);
+        max_seen = max(high, max_seen);
+        total += 1 + max_seen - new_low;
+    }
+    println!("Result {}", total);
+    Ok(())
+}