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y2019/p24.py

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+import sys
+from functools import lru_cache
+
+from toolkit import read_image
+
+
+def simple_adjace(level, pos):
+    inbound = {pos + ori for ori in [1, -1, 1j, -1j]} & domain
+    return [(level, p) for p in inbound]
+
+
+@lru_cache(maxsize=None)
+def recursive_adjace(level, pos, center=complex(2, 2)):
+    neis = []
+    for ori in [1, -1, 1j, -1j]:
+        adj = pos + ori
+        if adj == center:
+            neis += [(level + 1, p) for p in domain if p - ori not in domain]
+        elif adj not in domain:
+            neis += [(level - 1, center + ori)]
+        else:
+            neis += [(level, adj)]
+    return neis
+
+
+def evolve(bugs, adjacency, lim=None):
+    seen_states = set()
+    while lim is None or len(seen_states) < lim:
+        affected = {nei for tile in bugs for nei in adjacency(*tile)} | bugs
+        infested = set()
+        dead = set()
+
+        for tile in affected:
+            count = sum(nei in bugs for nei in adjacency(*tile))
+            if tile in bugs and count != 1:
+                dead.add(tile)
+            elif tile not in bugs and count in [1, 2]:
+                infested.add(tile)
+
+        bugs = bugs - dead | infested
+        if bugs in seen_states:
+            break
+        seen_states.add(bugs)
+    return bugs
+
+
+text = sys.stdin.read()
+domain = set(read_image(text))
+bugs = frozenset((0, pos) for pos, c in read_image(text).items() if c == '#')
+
+final = evolve(bugs, simple_adjace)
+print(int(sum(2 ** (p.real + p.imag * 5) for _, p in final)))
+
+final = evolve(bugs, recursive_adjace, 200)
+print(len(final))