Go back to fastest version

Author: EbbDrop

src/day23.rs

@@ -15,10 +15,7 @@ const MAX_C: usize = 13;
 pub fn part1(s: &str) -> u64 {
     let s = s.as_bytes();
 
-    let mut g = BitArray::<[u64; BAL]>::default();
-
-    let mut connections = heapless::Vec::<(u16, u16), 3380>::new();
-
+    let mut connections = [const { heapless::Vec::<u16, 16>::new() }; MAX];
     unsafe {
         let mut i = 0;
         while i < s.len() {
@@ -29,27 +26,42 @@ pub fn part1(s: &str) -> u64 {
             let cp1 = (cp1 + T_START_REM) % MAX as u16;
             let cp2 = (cp2 + T_START_REM) % MAX as u16;
 
-            if *s.get_unchecked(i) == b't' {
-                connections.push_unchecked((cp1, cp2));
-            } else if *s.get_unchecked(i + 3) == b't' {
-                connections.push_unchecked((cp2, cp1));
-            }
-            g.set(cp2 as usize * MAX + cp1 as usize, true);
-            g.set(cp1 as usize * MAX + cp2 as usize, true);
+            connections
+                .get_unchecked_mut(cp1 as usize)
+                .push_unchecked(cp2);
+            connections
+                .get_unchecked_mut(cp2 as usize)
+                .push_unchecked(cp1);
 
             i += 6;
         }
 
+        // println!(
+        //     "{}{}:",
+        //     ((c / 26) as u8 + b'a') as char,
+        //     ((c % 26) as u8 + b'a') as char,
+        // );
+
         let mut sum = 0;
-        for (a, b) in connections {
-            for i in b as usize..MAX {
-                if *g.get_unchecked(a as usize * MAX + i as usize)
-                    && *g.get_unchecked(b as usize * MAX + i as usize)
-                {
-                    sum += 1;
+        for c in 0..26 {
+            for con in &connections[c as usize] {
+                if *con < c {
+                    continue;
+                }
+                for concon in &connections[*con as usize] {
+                    if *concon < *con {
+                        continue;
+                    }
+                    for conconcon in &connections[*concon as usize] {
+                        if *conconcon == c {
+                            sum += 1;
+                            break;
+                        }
+                    }
                 }
             }
         }
+
         sum
     }
 }