[py] Simplify 2022_05

py/aoc/y2022/d05.py

@@ -1,32 +1,24 @@
 def solve(inputstr):
     stackstr, movestr = inputstr.split("\n\n")
 
-    stacks = []
-    for line in stackstr.splitlines()[:-1]:
-        i = 0
-        while line:
-            crate, line = line[:3], line[4:]
-            if len(stacks) <= i:
-                stacks.append([])
-            if crate[0] == "[":
-                stacks[i].append(crate[1])
-            i += 1
-    for stack in stacks:
-        stack.reverse()
+    stacklines = stackstr.splitlines()[:-1]
+    stacks = [[] for _ in range((len(stacklines[-1]) + 1) // 4)]
+    for line in stacklines[::-1]:
+        for i, c in enumerate(line[1::4]):
+            if c != " ":
+                stacks[i].append(c)
 
     moves = []
     for line in movestr.splitlines():
         _, amount, _, source, _, target = line.split()
         moves.append((int(amount), int(source), int(target)))
 
-    # Part 1
     part1 = [list(stack) for stack in stacks]
     for amount, source, target in moves:
-        for _ in range(amount):
-            part1[target - 1].append(part1[source - 1].pop())
+        part1[target - 1].extend(part1[source - 1][-amount:][::-1])
+        part1[source - 1] = part1[source - 1][:-amount]
     print("Part 1:", "".join(stack[-1] for stack in part1))
 
-    # Part 2
     part2 = [list(stack) for stack in stacks]
     for amount, source, target in moves:
         part2[target - 1].extend(part2[source - 1][-amount:])