2018 Day 12 proper

2018/day12.py

@@ -1,34 +1,41 @@
 with open('day12-input', 'r') as file:
   data = [l.strip('\n') for l in file]
 import numpy as np
-import re
 
-# numbers = np.array([[int(s) for s in re.findall(r'-?\d+', d)] for d in data], dtype=np.int64)
-max_gens = 50000000000
-
-initial_state = np.array([0 if s=='.' else 1 for s in data[0].split()[-1]])
-rules = [np.array([0 if s=='.' else 1 for s in d.split()[0]]+[0 if s=='.' else 1 for s in d.split()[-1]]) for d in data[2:]]
+initial_state = np.array([False if s=='.' else True for s in data[0].split()[-1]], dtype=np.bool)
+rules_list = [(sum([0 if s=='.' else 2**i for i, s in enumerate(d.split()[0])]), False if d.split()[-1] == '.' else True)
+              for d in data[2:]]
+rules = np.array([v for k, v in sorted(rules_list)], dtype=np.bool)
+r_transform = np.array([1, 2, 4, 8, 16], dtype=np.int64)
+state = set(*initial_state.nonzero())
 
 
-l = len(initial_state)
-state = np.zeros(l*20, dtype=np.int64)
-state[l*10:l*11] = initial_state
-last_state = state.copy()
-pots = np.arange(-l*10, l*10)
+def perform_generation(input_state):
+  working_state = set()
+  adj = np.array([-2, -1, 0, 1, 2], dtype=np.int64)
+  check_set = {i+j for i in input_state for j in adj}
+  for pot in check_set:
+    if rules[(r_transform * [p in input_state for p in pot+adj]).sum()]:
+      working_state.add(pot)
+  return working_state
 
-for gen in range(max_gens):
-  print(''.join(['#' if s else '.' for s in state[l*10-2:l*11+5]]), gen, max_gens-gen)
-  for plant in range(2, len(state)-2):
-    s = last_state[plant-2:plant+3]
-    matched = False
-    for rule in rules:
-      if np.array_equal(rule[:-1], s):
-        state[plant] = rule[-1]
-        # print('Matched!', rule)
-        matched = True
+
+for gen in range(20):
+  state = perform_generation(state)
+val = sum(state)
+print(val)  # Part 1
+
+state_2 = state.copy()
+last_val = val
+last_deltas = [None, None, None, None]
+LAST_GEN = 50000000000
+for gen in range(20, LAST_GEN):
+  if gen % 20 == 0:
+    val = sum(state_2)
+    last_deltas.append(val-last_val)
+    last_val = val
+    if len(set(last_deltas)) == 1:  # If all the last few deltas are identical, give up
+      print(val + (last_deltas[0]*(LAST_GEN-gen)//20))  # Part 2
       break
-    if not matched:
-      state[plant] = 0
-  last_state[:] = state[:]
-
-print(pots[state > 0].sum())
+    last_deltas.pop(0)
+  state_2 = perform_generation(state_2)