solve day 5 part a

5/supplystacks.py

@@ -0,0 +1,60 @@
+from copy import deepcopy
+from aocd.models import Puzzle
+from aocd import submit
+
+
+def rearrange_stacks(stacks: dict, moves: list) -> str:
+    """
+    execute moves on the stacks and return the top of each stack
+    """
+    # take a deep copy so embedded list do not get messed up
+    stacks = deepcopy(stacks)
+    # for each move, execute on stacks
+    for amount, index, dest in moves:
+        for i in range(amount):
+            stacks[dest].append(stacks[index].pop())
+    # 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:
+        stacks_str -> dict of moves {'index':['A','B','C']}
+        moves_str -> list of opeations [amount, index, dest]
+    """
+    # get input data
+    stacks_str, moves_str = data.split("\n\n")
+    # transpose field for easier parsing (thx linalg course)
+    transposed_stacks = list(map(list, zip(*stacks_str.splitlines())))
+    # parse stacks
+    stacks = {}
+    for line in transposed_stacks[1::4]:
+        stack = [c for c in line if c != " "]
+        key = stack.pop()
+        stack.reverse()
+        stacks[key] = stack
+    # parse moves
+    moves = []
+    for move in moves_str.splitlines():
+        _, amount, _, index, _, dest = move.split(" ")
+        # print(f'move {amount} from {index} to {dest}')
+        moves.append((int(amount), index, dest))
+    # return parsed data
+    return stacks, moves
+
+
+if __name__ == "__main__":
+    # get puzzle and parse data
+    puzzle = Puzzle(year=2022, day=5)
+    stacks, moves = parse_input(puzzle.input_data)
+
+    # part a:
+    answer_a = rearrange_stacks(stacks, moves)
+    print(f"{answer_a}")
+    submit(answer_a, part="a", day=5, year=2022)
+
+    # part b:
+    answer_b = 0
+    print(f"{answer_b}")
+    # submit(answer_b, part="b", day=5, year=2022)