day 5, but mildly less cursed

day05.py

@@ -1,42 +1,27 @@
 import fileinput
+import sys
 from collections import defaultdict, deque
 import re
 from copy import deepcopy
 
-input = fileinput.input()
-stacks: list[deque] = []
-
-for y, line in enumerate(input):
-    line = line.rstrip("\n")
-    if "1" in line:
-        continue
-    if not line:
-        break
-
-    for x in range(0, len(line), 4):
-        if y == 0:
-            stacks.append(deque([line[x + 1]] if line[x + 1] != " " else []))
-        elif line[x + 1] != " ":
-            stacks[x // 4].appendleft(line[x + 1])
+input = sys.stdin.read().split("\n")
 
+rows = (line[1::4] for line in input[::-1] if "[" in line)
+stacks = [[c for c in x if c != ' '] for x in zip(*rows)]
 stacks2 = deepcopy(stacks)
-
+        
 RE = re.compile(r"move (\d+) from (\d+) to (\d+)")
 for line in input:
     m = RE.match(line)
     if not m:
         continue
 
-    n, f, t = int(m[1]), int(m[2]), int(m[3])
+    n, f, t = int(m[1]), int(m[2]) - 1, int(m[3]) - 1
 
-    p2stack = []
-    for _ in range(n):
-        c = stacks[f - 1].pop()
-        stacks[t - 1].append(c)
+    stacks[t].extend(reversed(stacks[f][-n:]))
+    del stacks[f][-n:]
 
-        c = stacks2[f - 1].pop()
-        p2stack.append(c)
-
-    stacks2[t - 1].extend(reversed(p2stack))
+    stacks2[t].extend(stacks2[f][-n:])
+    del stacks2[f][-n:]
 
 print("".join(s[-1] for s in stacks), "".join(s[-1] for s in stacks2))