Update part 2

Author: EbbDrop

src/day8.rs

@@ -90,9 +90,9 @@ unsafe fn part1_inner(s: &str) -> u32 {
                 let node_y = new_y + diff_y;
 
                 *antinodes.get_unchecked_mut(node_y as usize) |= if diff_x.is_positive() {
-                    1 << new_x << diff_x
+                    1 << new_x >> diff_x
                 } else {
-                    1 << new_x >> -diff_x
+                    1 << new_x << -diff_x
                 };
             }
         }
@@ -120,78 +120,112 @@ unsafe fn part1_inner(s: &str) -> u32 {
 }
 
 #[aoc(day8, part2)]
-pub fn part2(s: &str) -> u64 {
-    #[expect(unused_unsafe)]
-    unsafe {
-        part2_inner(s)
-    }
+pub fn part2(s: &str) -> u32 {
+    unsafe { part2_inner(s) }
 }
 
-fn part2_inner(s: &str) -> u64 {
+unsafe fn part2_inner(s: &str) -> u32 {
+    #[cfg(not(test))]
+    const SIZE: i16 = 50;
+    #[cfg(test)]
+    const SIZE: i16 = 12;
+
+    const SIZE1: i16 = SIZE + 1;
+
     let s = s.as_bytes();
 
-    let mut masts: [ArrayVec<[i32; 4]>; FREQ_RANGE] =
-        [ArrayVec::from_array_empty([0; 4]); FREQ_RANGE];
+    let mut masts: [ArrayVec<[(i16, i16); 3]>; FREQ_RANGE] =
+        [ArrayVec::from_array_empty([(0, 0); 3]); FREQ_RANGE];
 
-    let mut antinodes = [false; (SIZE * SIZE) as usize];
-    let mut total_antinotedes = 0;
-    let mut set_node = |x, y| {
-        total_antinotedes += !antinodes[(y * SIZE + x) as usize] as u64;
-        antinodes[(y * SIZE + x) as usize] = true;
-    };
+    let mut antinodes = [0u64; SIZE as usize];
 
     for i in unsafe { OneInv::new_unchecked(b'.').iter(s) } {
         if s[i] == b'\n' {
             continue;
         }
         let f = s[i] - b'0';
-        let i = i as i32;
+        let i = i as i16;
 
         let new_x = i % SIZE1;
         let new_y = i / SIZE1;
-        for mast_i in &masts[f as usize] {
-            let mast_x = mast_i % SIZE1;
-            let mast_y = mast_i / SIZE1;
 
-            let o_diff_x = mast_x - new_x;
-            let o_diff_y = (new_y - mast_y).abs() as i32;
+        // numbers[masts[f as usize].len()] += 1;
+
+        for (mast_y, mast_x) in masts.get_unchecked(f as usize) {
+            let diff_x_o = mast_x - new_x;
+            let diff_y_o = new_y - mast_y;
 
             for k in 0.. {
-                let diff_x = o_diff_x * k;
-                let diff_y = o_diff_y * k;
+                let diff_x = diff_x_o * k;
+                let diff_y = diff_y_o * k;
 
-                let node_x = mast_x + diff_x;
-                if node_x >= 0 && node_x < SIZE && mast_y >= diff_y {
+                if *mast_y >= diff_y {
                     let node_y = mast_y - diff_y;
-                    set_node(node_x, node_y);
+
+                    let field = if diff_x.is_positive() {
+                        1 << mast_x << diff_x
+                    } else {
+                        1 << mast_x >> -diff_x
+                    };
+                    if field == 0 {
+                        break;
+                    } else {
+                        *antinodes.get_unchecked_mut(node_y as usize) |= field;
+                    }
                 } else {
                     break;
                 }
             }
 
             for k in 0.. {
-                let diff_x = o_diff_x * k;
-                let diff_y = o_diff_y * k;
+                let diff_x = diff_x_o * k;
+                let diff_y = diff_y_o * k;
 
-                let node_x = new_x - diff_x;
-                if node_x >= 0 && node_x < SIZE && new_y + diff_y < SIZE {
+                if new_y + diff_y < SIZE {
                     let node_y = new_y + diff_y;
-                    set_node(node_x, node_y);
+
+                    let field = if diff_x.is_positive() {
+                        1 << new_x >> diff_x
+                    } else {
+                        1 << new_x << -diff_x
+                    };
+                    if field == 0 {
+                        break;
+                    } else {
+                        *antinodes.get_unchecked_mut(node_y as usize) |= field;
+                    }
                 } else {
                     break;
                 }
             }
         }
 
-        masts[f as usize].push(i);
+        masts[f as usize].try_push((new_y, new_x));
     }
+    // for y in 0..SIZE {
+    //     for x in 0..SIZE {
+    //         print!(
+    //             "{}",
+    //             if antinodes[y as usize] & 1 << x != 0 {
+    //                 '#'
+    //             } else {
+    //                 s[(y * SIZE1 + x) as usize] as char
+    //             }
+    //         )
+    //     }
+    //     println!("");
+    // }
 
-    total_antinotedes
+    antinodes
+        .iter()
+        .map(|field| (field & FIELD_SIZE).count_ones())
+        .sum()
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
+
     const EXAMPLE: &str = r"............
 ........0...
 .....0......