Aaaaaa

day14.py

@@ -0,0 +1,58 @@
+import sys
+from pprint import pprint
+from copy import deepcopy
+
+def shift(map, dx, dy):
+    swapped = True
+    while swapped:
+        swapped = False
+        for y in range(max(0, -dy), len(map) - max(0, dy)):
+            for x in range(max(0, -dx), len(map) - max(0, dx)):
+                if map[y + dy][x + dx] == "." and map[y][x] == "O":
+                    map[y + dy][x + dx] = "O"
+                    map[y][x] = "."
+                    swapped = True
+
+def weigh(map):
+    return sum((len(map) - y) * row.count("O") for (y, row) in enumerate(map))
+
+CYCLES = 1_000_000_000
+
+def main():
+    with open(sys.argv[1]) as f:
+        map = [list(l) for l in f.read().strip().splitlines()]
+
+    part1 = 0
+    shift(map, 0, -1)
+    part1 = weigh(map)
+
+    seen = {}
+    history = []
+    for i in range(CYCLES):
+        shift(map, 0, -1)
+        if i == 0: pprint(map)
+        shift(map, -1, 0)
+        if i == 0: pprint(map)
+        shift(map, 0, 1)
+        if i == 0: pprint(map)
+        shift(map, 1, 0)
+        if i == 0: pprint(map)
+
+        s = str(map)
+        if s in seen:
+            break
+        seen[s] = i
+        history.append(weigh(map))
+
+    j = seen[s]
+    offset = (CYCLES - j) % (i + 1 - j) + j
+    part2 = history[offset]
+
+    print(part1, part2)
+
+
+main()
+
+# 98887 too low
+# 98898 too high
+# 103761 too high