day-5/src/main.rs

@@ -17,6 +17,26 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     println!("{}", max_id?);
 
+    // Part 2
+    let mut ids = input
+        .lines()
+        .map(|code| {
+            let (row, col) = find_seat(parse_seatcode(code)?);
+            Ok(row * 8 + col)
+        })
+        .collect::<Result<Vec<usize>, String>>()?;
+    ids.sort();
+
+    let mut previous = ids[0];
+    for id in &ids[1..] {
+        if id - 1 != previous {
+            println!("{}", id);
+            break;
+        } else {
+            previous = *id;
+        }
+    }
+
     Ok(())
 }