2024 - Day 22: Monkey Market

2024/day22.py

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+from day_base import Day
+
+
+def calculate_next_number(secret_number):
+    # Multiply by 64 and mix
+    new_number = secret_number << 6
+    secret_number = secret_number ^ new_number
+    secret_number = secret_number & (16777216 - 1)
+    # Divide by 32 and mix, and prune
+    new_number = secret_number >> 5
+    secret_number = secret_number ^ new_number
+    secret_number = secret_number & (16777216 - 1)
+    # Multiply by 2048 and mix,
+    new_number = secret_number << 11
+    secret_number = secret_number ^ new_number
+    secret_number = secret_number & (16777216 - 1)
+    return secret_number
+
+
+class Day22(Day):
+
+    def __init__(self):
+        super().__init__(2024, 22, 'Monkey Market', debug=False)
+
+    def part_a(self):
+        total = 0
+        for secret_number in self.input:
+            secret_number = int(secret_number)
+            for _ in range(2000):
+                secret_number = calculate_next_number(secret_number)
+            total += secret_number
+
+        return total
+
+    def part_b(self) -> int:
+        buyers = []
+        for secret_number in self.input:
+            secret_number = int(secret_number)
+            buyer = [secret_number % 10]
+
+            for _ in range(2000):
+                secret_number = calculate_next_number(secret_number)
+                buyer.append(secret_number % 10)
+
+            buyers.append(buyer)
+
+        # Find the prices for each sequence
+        buyer_sequence = dict()
+        for buyer_idx, buyer in enumerate(buyers):
+            seen_sequences = set()
+            for i in range(2000 - 5):
+                d1, d2, d3, d4 = buyer[i + 1] - buyer[i], buyer[i + 2] - buyer[i + 1], buyer[i + 3] - buyer[i + 2], buyer[i + 4] - buyer[i + 3]
+                sequence = (d1, d2, d3, d4)
+                price = buyer[i + 4]
+
+                if sequence in seen_sequences:
+                    continue
+                seen_sequences.add(sequence)
+
+                if sequence not in buyer_sequence.keys():
+                    buyer_sequence[sequence] = 0
+                buyer_sequence[sequence] += price
+
+        max_sequence = max(buyer_sequence.keys(), key=lambda k: buyer_sequence[k])
+
+        return buyer_sequence[max_sequence]
+
+
+
+if __name__ == '__main__':
+    (Day22()).run()
+