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src/day15.rs

@@ -73,7 +73,14 @@ unsafe fn part2_inner(input: &[u8]) -> usize {
     let mut i = 0;
     for _ in 0..20 {
         for _ in 0..1000 {
-            let dir = *P2_DIRECTION_LUT.get_unchecked(directions[i] as usize);
+            let dir = match directions[i] {
+                b'^' => -100,
+                b'>' => 1,
+                b'v' => 100,
+                b'<' => -1,
+                _ => unreachable_unchecked(),
+            };
+            // let dir = *P2_DIRECTION_LUT.get_unchecked(directions[i] as usize);
             i += 1;
             let next_pos = pos.wrapping_add_signed(dir);
             if !can_push_box(&grid, next_pos, dir) {
@@ -177,17 +184,12 @@ unsafe fn push_box_vertical(grid: &mut [u8; 100 * 50], pos: usize, dir: isize) {
     }
 }
 
-macro_rules! direction_lut {
-    ($vert: literal) => {{
-        let mut lut = [0; LARGEST_DIRECTION];
-        lut[b'^' as usize] = -$vert;
-        lut[b'>' as usize] = 1;
-        lut[b'v' as usize] = $vert;
-        lut[b'<' as usize] = -1;
-        lut
-    }};
-}
-
 const LARGEST_DIRECTION: usize = b'v' as usize + 1;
-static P1_DIRECTION_LUT: [isize; LARGEST_DIRECTION] = direction_lut!(51);
-static P2_DIRECTION_LUT: [isize; LARGEST_DIRECTION] = direction_lut!(100);
+static P1_DIRECTION_LUT: [isize; LARGEST_DIRECTION] = {
+    let mut lut = [0; LARGEST_DIRECTION];
+    lut[b'^' as usize] = -51;
+    lut[b'>' as usize] = 1;
+    lut[b'v' as usize] = 51;
+    lut[b'<' as usize] = -1;
+    lut
+};