bwhitt7 performance improvements

README.md

@@ -1,5 +1,7 @@
 # Python Performance Lab: Sharpening Your Instincts
 
+This is bwhitt7's fork.
+
 A PyCon US 2026 hands-on tutorial. You optimize intentionally slow Python code
 across three rounds plus a team challenge, measuring every change with
 [CodSpeed](https://codspeed.io).

rounds/3_dna/solution.py

@@ -6,12 +6,46 @@
 """
 
 from .baseline import find_matches as _baseline
+from concurrent.futures import ThreadPoolExecutor
+import threading
+import os
 
+def _thread_worker(pattern_str: str, record: str, matches, lock:threading.Lock):
+    if not record.strip():
+        return
+    lines = record.split("\n")
+    record_id = lines[0].strip()
+    sequence = "".join(lines[1:]).replace(" ", "")
+    positions: list[int] = []
+    start = 0
+    while True:
+        pos = sequence.find(pattern_str, start)
+        if pos == -1:
+            break
+        positions.append(pos)
+        start = pos + 1
+
+    if positions:
+        with lock:
+            matches[record_id] = positions
 
 def find_matches(fasta_path: str, pattern: bytes) -> list[tuple[str, list[int]]]:
     """Find every FASTA record whose sequence contains ``pattern``.
 
     Returns ``[(record_id, [positions...]), ...]`` in file order.
     """
-    # TODO: remove this delegation and write your own implementation here.
-    return _baseline(fasta_path, pattern)
+    pattern_str = pattern.decode("ascii")
+    with open(fasta_path, "r") as f:
+        text = f.read()
+
+    matches: dict[str, list[int]] = {}
+
+    lock = threading.Lock()
+    with ThreadPoolExecutor(max_workers=os.cpu_count()) as executor:
+        executor.map(lambda args: _thread_worker(*args),
+                     [
+                         (pattern_str, record, matches, lock)
+                         for record in text.split(">")
+                     ])
+    matches = dict(sorted(matches.items()))
+    return [(k,v) for k,v in matches.items()]