Implement day 22 part 1

2019/aoc2019/day22.py

@@ -0,0 +1,44 @@
+from typing import List, TextIO
+
+
+def shuffle(instructions: List[str], deck_size: int) -> List[int]:
+    deck = list(range(0, deck_size))
+
+    for instruction in instructions:
+        if "new stack" in instruction:
+            deck = list(reversed(deck))
+            continue
+
+        parts = instruction.split(" ")
+        if parts[0] == "cut":
+            by = int(parts[1])
+
+            new_deck = deck[by:]
+            new_deck += deck[:by]
+
+            deck = new_deck
+        else:
+            increment = int(parts[3])
+
+            new_deck = list(range(0, deck_size))
+            target_index = 0
+
+            for card in deck:
+                new_deck[target_index] = card
+                target_index = (target_index + increment) % len(deck)
+
+            deck = new_deck
+
+    return deck
+
+
+def part1(data: TextIO):
+    instructions = [line.strip() for line in data]
+
+    result = shuffle(instructions, 10007)
+
+    for i, card in enumerate(result):
+        if card == 2019:
+            return i
+
+    raise Exception("Did not find card")