The Cheapest city

We are in September 2022, the world has witnessed significant events over the past two years, like the global COVID-19 pandemic, the Russian invasion of Ukraine and the economic boycott imposed on Russia. These occurrences have had a profound and adverse impact on the international economy, leading to a surge in global inflation reminiscent of that in the 1920s.

As a result, people all over the world are dealing with the rising cost of living, which has hit unprecedented levels. Take Adnan, for example; he's a Moroccan citizen and, like many others, felt the impact. Luckily, Adnan turned Solo-preneur with the help of Djalal two years ago (Thanks Djalal) and now works remotely. This flexibility allows him to live anywhere in Morocco. That's when he got the idea to move to a city where the cost of products is more affordable since his wife isn’t against the idea 😁. Adnan starts analyzing rows of data (data <= 1,000,000,000 rows) to make a final decision. The data contains several Moroccan cities with the prices of different products.

Assist Adnan by writing a program, using any allowed language, to find the city with the lowest prices for products. The challenge is to write an optimized code that can handle large amounts of data and quickly return the sorted results.

• 1.00 <= price <= 100.00
• we have 101 cities.
• We have 100 products.
• Each city may have the same product duplicated several times with different or identical prices.
• Your code will process a 10^9 (1 billion) line CSV file.
• The input file is located on "input.txt"

• Output has 6 lines.
• The first line contains the name of the cheapest city and the total price of products in that city, separated by one space.
• The remaining 5 lines display the first 5 cheapest products sorted by price in ascending order. In the case of two products with the same price, they are sorted alphabetically. For example, "Potato" and "Tomato" in the output below
• Don't print the same product twice. If you have multiple instances of the same product in the top 5 cheapest products, only print the cheapest one.
• Like the 1st line, other lines have one space between the product and the price.
• All the prices are decimal and they have a scale of 2.
• Each line is trimmed (no spaces at the beginning or the end of each line).

• Make sure that your code is compiling. 😄 It may seem trivial, but sometimes we receive code that doesn't compile.
• Your solution needs to run under 15min. Any submission taking more than that will be discarded.
• If your solution is correct, we will count it and add your name to the leaderboard, if not we will discard it.
• Before creating the PR, your code has to produce the same result as the output below.
• You are allowed to submit the code several times with different langs.
• Each code will be reviewed manually. Any fraudulent attempt will result in your account being banned, and you will be disqualified from the challenge.
• Contestants are supposed to read input from the file in their current working directory named input.txt and write the output to a file in the same directory named output.txt.

Below are short examples for better understanding:

casa,tomato,6.23
casa,tomato,7.23
casa,tomato,8.23
casa,tomato,9.23
casa,potato,4.21
casa,flour,6.24
casa,oil,9.24
casa,oil,9.94
casa,oil,8.24
casa,sugar,5.23
casa,sugar,5.23
casa,sugar,5.23
casa,gaz,9.25
Tetouan,tomato,4.5
Tetouan,tomato,3.5
Tetouan,potato,3.5
Tetouan,flour,5.2
Tetouan,oil,7.7
Tetouan,oil,6.7
Tetouan,sugar,4.5
Tetouan,gaz,9.3
Tetouan,gaz,2.3
Tetouan,gaz,1.3
rabat,tomato,5.85
rabat,tomato,9.85
rabat,potato,4.65
rabat,flour,5.65
rabat,oil,8.15
rabat,oil,9.15
rabat,oil,7.15
rabat,sugar,9.05
rabat,sugar,9.15
rabat,gaz,9.45

Tetouan 48.50
gaz 1.30
potato 3.50
tomato 3.50
sugar 4.50
flour 5.20