2024 Day 22 Part 2 Complete

Author: pcorliss

2024/22/daily.py

@@ -9,7 +9,7 @@ def parse(input_text):
 
   return codes
 
-
+sum_sequence = {}
 def gen_code(secret_number, generation):
   def mix(s, code):
     return s ^ code
@@ -18,7 +18,10 @@ def prune(code):
     return code & 16777215 # 2**24 - 1
 
   code = secret_number
+  last_digit = code % 10
+  last_diff = [None, None, None, None]
 
+  gen_sequence = {}
   for i in range(generation):
     to_mix = code << 6 # multiply by 64
     code = mix(code, to_mix)
@@ -30,6 +33,27 @@ def prune(code):
     code = mix(code, to_mix)
     code = prune(code)
 
+    new_last_digit = code % 10
+    diff = new_last_digit - last_digit
+    last_diff = last_diff[1:]
+    last_diff.append(diff)
+
+    # We want the first sequence for this generation
+    sequence_key = tuple(last_diff)
+    if i > 2 and sequence_key not in gen_sequence:
+      # if sequence_key == (-2,1,-1,3):
+      #   print(f"{secret_number} - Sequence: {sequence_key} - G:{i} - C: {code} NLD: {new_last_digit} - LastDigit: {last_digit}")
+      gen_sequence[tuple(last_diff)] = new_last_digit
+
+    last_digit = new_last_digit
+
+  for k, v in gen_sequence.items():
+    if k not in sum_sequence:
+      sum_sequence[k] = 0
+    # if k == (-2,1,-1,3):
+    #   print(f"\tAdding {v} to {sum_sequence[k]}")
+    sum_sequence[k] += v
+
   return code
 
 def part1(input_text):
@@ -40,7 +64,23 @@ def part1(input_text):
   return sum
 
 def part2(input_text):
-  return 0
+  global sum_sequence
+  sum_sequence = {}
+  codes = parse(input_text)
+  for code in codes:
+    gen_code(code, 2000)
+
+  max_v = 0
+  max_s = None
+  print(f"Sum Sequence: {sum_sequence[(-2,1,-1,3)]}")
+  for k, v in sum_sequence.items():
+    if v > max_v:
+      max_v = v
+      max_s = k
+
+  return max_s, max_v
+
+# 3, 0, -5, -3 - not the right answer
 
 if __name__ == "__main__":
   with open(__file__.rsplit('/', 1)[0] + "/input.txt", 'r') as file:

2024/22/daily_test.py

@@ -10,6 +10,15 @@ def sample_data():
 2024
 """
 
+@pytest.fixture
+def sample_data_2():
+  return """
+1
+2
+3
+2024
+"""
+
 @pytest.fixture
 def parsed_data(sample_data):
   return parse(sample_data)
@@ -42,5 +51,7 @@ def test_gen_code(secret_number, generation, expected):
 def test_part1(sample_data):
   assert part1(sample_data) == 37327623
 
-# def test_part2(sample_data):
-#   assert part2(sample_data) == 154115708116294
+def test_part2(sample_data_2):
+  sequence, bananas = part2(sample_data_2)
+  assert sequence == (-2,1,-1,3)
+  assert bananas == 23