day19 cleanup

src/tasks/day19.rs

@@ -4,8 +4,8 @@ use itertools::Itertools;
 
 pub fn run() {
     let program = super::day05::load_ram("input/day19.txt");
-    //part1(&program, 50);
-    part2(&program); // 8151016 too high
+    part1(&program, 50);
+    part2(&program);
 }
 
 fn part1(program: &RAM, max: i128) {
@@ -20,7 +20,7 @@ fn part1(program: &RAM, max: i128) {
         .filter(|v| *v)
         .count();
 
-    println!("{result}");
+    println!("Part 1: {result}");
 }
 
 const W: i128 = 100;
@@ -35,29 +35,37 @@ fn part2(program: &RAM) {
                     map.insert((x, y), read_coordinate(program, x, y));
                 })
         });
-    for starts in 0..=MAX_PERIMETER {
-        println!("checking perimeter {starts}");
-        extend_horizon(program, &mut map, starts);
-        check_all_squares_at(&map, starts);
+    for perimeter in 0..=MAX_PERIMETER {
+        extend_horizon(program, &mut map, perimeter);
+        if let Some((x, y)) = check_all_squares_starting_at(&map, perimeter) {
+            let result = x * 10_000 + y;
+            println!("Part 2: starts at {x},{y} -> {}", result);
+            break;
+        }
     }
 }
 
-fn check_all_squares_at(map: &HashMap<(i128, i128), bool>, starts: i128) {
-    (0..=starts).for_each(|i| {
-        check_fits(map, i, starts);
-        check_fits(map, starts, i);
-    });
+fn check_all_squares_starting_at(map: &HashMap<(i128, i128), bool>, perimeter: i128) -> Option<(i128, i128)> {
+    for i in 0..=perimeter {
+        if let Some(point) = check_fits(map, i, perimeter) {
+            return Some(point);
+        }
+        if let Some(point) = check_fits(map, perimeter, i) {
+            return Some(point);
+        }
+    }
+    None
 }
 
-fn check_fits(map: &HashMap<(i128, i128), bool>, x: i128, y: i128) {
+fn check_fits(map: &HashMap<(i128, i128), bool>, x: i128, y: i128) -> Option<(i128, i128)> {
     let ul = map[&(x, y)];
     let ur = map[&(x + W - 1, y)];
     let ll = map[&(x, y + W - 1)];
     let lr = map[&(x + W, y + W - 1)];
     if ul && ur && ll && lr {
-        let result = x * 10_000 + y;
-        panic!("found it! starts at {x},{y} -> {}", result);
+        return Some((x, y));
     }
+    None
 }
 
 fn extend_horizon(program: &RAM, map: &mut HashMap<(i128, i128), bool>, starts: i128) {