solve part b

5/supplystacks.py

@@ -3,9 +3,10 @@ from aocd.models import Puzzle
 from aocd import submit
 
 
-def rearrange_stacks(stacks: dict, moves: list) -> str:
+def crate_mover_9000(stacks: dict, moves: list) -> str:
     """
     execute moves on the stacks and return the top of each stack
+    the crate mover 9000 only moves single crates.
     """
     # take a deep copy so embedded list do not get messed up
     stacks = deepcopy(stacks)
@@ -17,6 +18,21 @@ def rearrange_stacks(stacks: dict, moves: list) -> str:
     return "".join([stack[-1] for stack in stacks.values()])
 
 
+def crate_mover_9001(stacks: dict, moves: list) -> str:
+    """
+    execute moves on the stacks and return the top of each stack
+    the crate mover 9001 moves stacks of crates.
+    """
+    # take a deep copy so embedded list do not get messed up
+    stacks = deepcopy(stacks)
+    # for each move, move amount of crates from index to dest
+    for amount, index, dest in moves:
+        stacks[dest].extend(stacks[index][-amount:])
+        stacks[index] = stacks[index][:-amount]
+    # take the last element fom each stack and append to output
+    return "".join([stack[-1] for stack in stacks.values()])
+
+
 def parse_input(data: list) -> list:
     """
     turn input data into usable data types:
@@ -50,11 +66,11 @@ if __name__ == "__main__":
     stacks, moves = parse_input(puzzle.input_data)
 
     # part a:
-    answer_a = rearrange_stacks(stacks, moves)
+    answer_a = crate_mover_9000(stacks, moves)
     print(f"{answer_a}")
     submit(answer_a, part="a", day=5, year=2022)
 
     # part b:
-    answer_b = 0
+    answer_b = crate_mover_9001(stacks, moves)
     print(f"{answer_b}")
-    # submit(answer_b, part="b", day=5, year=2022)
+    submit(answer_b, part="b", day=5, year=2022)