h

day14.py

@@ -2,57 +2,72 @@ 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
+    for y in range(max(0, -dy), len(map) - max(0, dy)):
+        for x in range(max(0, -dx), len(map) - max(0, dx)):
+            (x1, y1) = (x, y)
+            while True:
+                (x2, y2) = (x1 + dx, y1 + dy)
+                if 0 <= y2 < len(map) and 0 <= x2 < len(map[y2]) and map[y2][x2] == ".":
+                    (x1, y1) = (x2, y2)
+                else:
+                    break
+
+            if (x1, y1) != (x, y):
+                map[y1][x1] = "O"
+                map[y][x] = "."
+
 
 def weigh(map):
     return sum((len(map) - y) * row.count("O") for (y, row) in enumerate(map))
 
-CYCLES = 1_000_000_000
 
+# @profile
 def main():
+    CYCLES = 1_000_000_000
+
     with open(sys.argv[1]) as f:
-        map = [list(l) for l in f.read().strip().splitlines()]
+        map = [[c for c in l] for l in f.read().strip().splitlines()]
 
     part1 = 0
+    pprint(map)
     shift(map, 0, -1)
+    pprint(map)
     part1 = weigh(map)
+    shift(map, -1, 0)
+    pprint(map)
+    shift(map, 0, 1)
+    pprint(map)
+    shift(map, 1, 0)
+    pprint(map)
+
+    for i in range(1, 100):
+        shift(map, 0, -1)
+        shift(map, -1, 0)
+        shift(map, 0, 1)
+        shift(map, 1, 0)
 
     seen = {}
     history = []
-    for i in range(CYCLES):
+    (i, j) = (0, 0)
+    for i in range(100, 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)
+        history.append(weigh(map))
         if s in seen:
+            j = seen[s]
             break
         seen[s] = i
-        history.append(weigh(map))
 
-    j = seen[s]
-    offset = (CYCLES - j) % (i + 1 - j) + j
+    offset = (CYCLES - j) % (i - j) - 1
     part2 = history[offset]
 
     print(part1, part2)
 
 
 main()
-
-# 98887 too low
-# 98898 too high
-# 103761 too high

day15.py

@@ -2,7 +2,8 @@ import os
 import sys
 from collections import defaultdict
 
-def hash(s):
+
+def hash(s: str) -> int:
     v = 0
     for c in s:
         if c == ",":
@@ -12,36 +13,42 @@ def hash(s):
         v %= 256
     return v
 
-with open(sys.argv[1]) as f:
-    s = f.read().strip()
 
-boxes = defaultdict(list)
+def main() -> None:
+    with open(sys.argv[1]) as f:
+        s = f.read().strip()
 
-part1 = 0
-for s_ in s.split(","):
-    part1 += hash(s_)
+    boxes: defaultdict[int, list[tuple[str, int]]] = defaultdict(list)
 
-    if s_[-1] == "-":
-        label = s_[:-1]
-        h = hash(label)
-        for i in range(len(boxes[h])):
-            if boxes[h][i][0] == label:
-                del boxes[h][i]
-                break
-    elif s_[-2] == "=":
-        label = s_[:-2]
-        focal = int(s_[-1])
-        h = hash(label)
-        for i in range(len(boxes[h])):
-            if boxes[h][i][0] == label:
-                boxes[h][i] = (label, focal)
-                break
-        else:
-            boxes[h].append((label, focal))
+    part1 = 0
+    for s_ in s.split(","):
+        part1 += hash(s_)
 
-part2 = 0
-for (box_i, box) in boxes.items():
-    for (slot, (_, focal)) in enumerate(box):
-        part2 += (box_i + 1) * (slot + 1) * focal
+        if s_[-1] == "-":
+            label = s_[:-1]
+            h = hash(label)
+            for i in range(len(boxes[h])):
+                if boxes[h][i][0] == label:
+                    del boxes[h][i]
+                    break
+        elif s_[-2] == "=":
+            label = s_[:-2]
+            focal = int(s_[-1])
+            h = hash(label)
+            for i in range(len(boxes[h])):
+                if boxes[h][i][0] == label:
+                    boxes[h][i] = (label, focal)
+                    break
+            else:
+                boxes[h].append((label, focal))
 
-print(part1, part2)
+    part2 = 0
+    for (box_i, box) in boxes.items():
+        for (slot, (_, focal)) in enumerate(box):
+            part2 += (box_i + 1) * (slot + 1) * focal
+
+    print(part1, part2)
+
+
+if __name__ == "__main__":
+    main()