Untitled

import csv
from collections import defaultdict

def generateFiles(input_file_name):
    product_data = defaultdict(lambda: {'quantity_sum': 0, 'count': 0, 'brands': defaultdict(int)})

    # Process the input file in one pass
    with open(input_file_name, mode='r') as file:
        reader = csv.reader(file)
        for row in reader:
            product = row[2]
            quantity = int(row[3])
            brand = row[4]

            # Update quantity and count
            product_data[product]['quantity_sum'] += quantity
            product_data[product]['count'] += 1

            # Update brand popularity count
            product_data[product]['brands'][brand] += 1

    # Write the first output file: 0_input_file_name.csv
    output_file_0 = '0_' + input_file_name
    with open(output_file_0, mode='w', newline='') as file:
        writer = csv.writer(file)
        for product, data in product_data.items():
            avg_quantity = data['quantity_sum'] / data['count']
            writer.writerow([product, f'{avg_quantity:.3f}'])

    # Write the second output file: 1_input_file_name.csv
    output_file_1 = '1_' + input_file_name
    with open(output_file_1, mode='w', newline='') as file:
        writer = csv.writer(file)
        for product, data in product_data.items():
            most_popular_brand = max(data['brands'], key=data['brands'].get)
            writer.writerow([product, most_popular_brand])

# Example usage
if __name__ == '__main__':
    input_file_name = input()
    generateFiles(input_file_name)