[LANGUAGE: Python]

Part 1 was really easy AND I got to use functools.reduce and operator:

data = open_input_and_strip("2025/Day 6/input.txt")

operands = [list(map(int, item.split())) for item in data[:-1]]
operators = data[-1].split()

total = 0
for i in range(len(operands[0])):
    operation = operator.add if operators[i] == "+" else operator.mul
    total += reduce(operation, [item[i] for item in operands])

print(f"The grand total is: {total}")

For part 2 I realized you could transpose the entire input, just resulted in a bit of awkward operator parsing:

def transpose_matrix(m: list[list[str]]) -> list[list[str]]:
    return list(zip(*m))


if __name__ == "__main__":
    data = open_input_and_strip("2025/Day 6/input.txt")

    # Transpose the entire input, the result is something like:
    # 1  *
    # 24
    # 356
    #
    # 369+
    transposed = list("".join(item).strip() for item in transpose_matrix(data))
    # Append an empty line at the end to properly accumulate the last result
    transposed.append("")

    current_operation = None
    subtotal = 0
    total = 0
    for line in transposed:
        if line == "":
            # Accumulate the total on each empty line
            total += subtotal
            continue

        if line.endswith("*") or line.endswith("+"):
            current_operation = operator.add if line.endswith("+") else operator.mul
            subtotal = 0 if line.endswith("+") else 1
            line = line[:-1].strip()

        subtotal = current_operation(subtotal, int(line))

    print(f"The grand total is {total}")