Merge pull request #215 from ephemient/py/day19

py/aoc2024/day19.py

@@ -2,6 +2,8 @@
 Day 19: Linen Layout
 """
 
+from aoc2024.day19c import solve as _solve
+
 SAMPLE_INPUT = """\
 r, wr, b, g, bwu, rb, gb, br
 
@@ -16,15 +18,6 @@
 """
 
 
-def _count(keys: list[str], target: str) -> int:
-    counts = [1]
-    for i in range(1, len(target) + 1):
-        counts.append(
-            sum(counts[i - len(key)] for key in keys if target[:i].endswith(key))
-        )
-    return counts[-1]
-
-
 def solve(data: str) -> str:
     """
     >>> print(solve(SAMPLE_INPUT))
@@ -33,12 +26,7 @@ def solve(data: str) -> str:
     """
     keys, *targets = data.splitlines()
     keys = keys.split(", ")
-    part1, part2 = 0, 0
-    for target in targets:
-        n = _count(keys, target) if target else None
-        if n:
-            part1 += 1
-            part2 += n
+    part1, part2 = _solve(keys, targets)
     return f"{part1}\n{part2}"
 
 

py/aoc2024/day19c.py

@@ -0,0 +1,46 @@
+# cython: boundscheck=False, wraparound=False, initializedcheck=False, embedsignature=True
+import cython
+from collections.abc import Collection
+from cython.cimports.cpython.mem import PyMem_Free, PyMem_Realloc
+from cython.cimports.cpython.unicode import PyUnicode_Tailmatch
+
+
+@cython.ccall
+def solve(
+    keys: Collection[str], targets: Collection[str]
+) -> tuple[cython.int, cython.long]:
+    i: cython.int
+    j: cython.int
+    k: cython.int
+    numkeys: cython.int = len(keys)
+    numtargets: cython.int = len(targets)
+    counts: cython.p_long = cython.NULL
+    numcounts: cython.int = 0
+    part1: cython.int = 0
+    part2: cython.long = 0
+    try:
+        for i in range(numtargets):
+            target: str = targets[i]
+            if not target:
+                continue
+            targetlen: cython.int = len(target)
+            if numcounts < targetlen + 1:
+                numcounts = targetlen + 1
+                counts = cython.cast(
+                    cython.p_long,
+                    PyMem_Realloc(counts, numcounts * cython.sizeof(cython.long)),
+                )
+            counts[0] = 1
+            for j in range(1, targetlen + 1):
+                counts[j] = 0
+                for k in range(numkeys):
+                    key: str = keys[k]
+                    keylen: cython.int = len(key)
+                    if PyUnicode_Tailmatch(target, key, 0, j, 1) == 1:
+                        counts[j] += counts[j - keylen]
+            n: cython.long = counts[targetlen]
+            part1 += 1 if n else 0
+            part2 += n
+        return part1, part2
+    finally:
+        PyMem_Free(counts)