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Past editions

Hash Code started in 2014 as a one-day programming competition for students and professionals from across France. We introduced the Online Qualification Round in 2015 where more than 1,500 students and professionals competed. In 2016 we scaled the competition to the rest of Europe, the Middle East and Africa where more than 17,000 people signed up to compete. In 2017, more than 26,000 people competed. You can take a look at the problems and winning teams from past editions of Hash Code below.

Past problem statements

Wifi Routers
Router placement
Hash Code 2017, Final Round
Who doesn't love wireless Internet? Millions of people rely on it for productivity and fun in countless cafes, railway stations and public areas of all sorts. For many institutions, ensuring wireless Internet access is now almost as important a feature of building facilities as the access to water and electricity. Typically, buildings are connected to the Internet using a fiber backbone. In order to provide wireless Internet access, wireless routers are placed around the building and connected using fiber cables to the backbone. The larger and more complex the building, the harder it is to pick router locations and decide how to lay down the connecting cables.
Satellites Photo
Streaming videos
Hash Code 2017, Online Qualification Round
Have you ever wondered what happens behind the scenes when you watch a YouTube video? As more and more people watch online videos (and as the size of these videos increases), it is critical that video-serving infrastructure is optimized to handle requests reliably and quickly. This typically involves putting in place cache servers, which store copies of popular videos. When a user request for a particular video arrives, it can be handled by a cache server close to the user, rather than by a remote data center thousands of kilometers away. Given a description of cache servers, network endpoints and videos, along with predicted requests for individual videos, decide which videos to put in which cache server in order to minimize the average waiting time for all requests.
Satellites Photo
Hash Code 2016, Final Round
A satellite equipped with a high-resolution camera can be an excellent source of geo imagery. While harder to deploy than a plane or a Street View car, a satellite — once launched — provides a continuous stream of fresh data. Terra Bella is a division within Google that deploys and manages high-resolution imaging satellites in order to capture rapidly-updated imagery and analyze them for commercial customers. With a growing constellation of satellites and a constant need for fresh imagery, distributing the work between the satellites is a major challenge. Given a set of imaging satellites and a list of image collections ordered by customers, schedule satellite operations so that the total value of delivered image collections is as high as possible.
Google Wing Project
Hash Code 2016, Online Qualification Round
The Internet has profoundly changed the way we buy things, but the online shopping of today is likely not the end of that change; after each purchase we still need to wait multiple days for physical goods to be carried to our doorstep. Given a fleet of drones, a list of customer orders and availability of the individual products in warehouses, schedule the drone operations so that the orders are completed as soon as possible.
Loon Project
Hash Code 2015, Final Round
Project Loon aims to bring universal Internet access using a fleet of high altitude balloons equipped with LTE transmitters. Circulating around the world, Loon balloons deliver Internet access in areas that lack conventional means of Internet connectivity. Given the wind data at different altitudes, plan altitude adjustments for a fleet of balloons to provide Internet coverage to select locations.
Google Data Center
Optimize a data center
Hash Code 2015, Online Qualification Round
For over ten years, Google has been building data centers of its own design, deploying thousands of machines in locations around the globe. In each of these of locations, batteries of servers are at work around the clock, running services we use every day, from Google Search and YouTube to the Judge System of Hash Code. Given a schema of a data center and a list of available servers, your task is to optimize the layout of the data center to maximize its availability.
A StreetView Car
Street View routing
Hash Code 2014, Final Round
The Street View imagery available in Google Maps is captured using specialized vehicles called Street View cars. These cars carry multiple cameras capturing pictures as the car moves around a city. Capturing the imagery of a city poses an optimization problem: the fleet of cars is available for a limited amount of time and we want to cover as much of the city streets as possible.

Hall of fame

Winners of the 2017 edition of the Hash Code

Hash Code 2017

AIM Tech
Ivan Fefer (AIM Tech, Russia)
Aleksei Safronov (AIM Tech, Russia)
Renat Gimadeev (AIM Tech, Russia)
Artem Verkhoglyadov (AIM Tech, Russia)

Winners of the 2016 edition of the Hash Code

Hash Code 2016

Sergei Zhgirovski (Yandex, Belarus)
Roman Udovichenko (Yandex, Belarus)

Winners of
            the 2015 edition of the Hash Code

Hash Code 2015

ENS Ulm 1
Antoine Amarilli (ENS Paris, France)
Auguste Olivry (ENS Paris, France)
Marc Jeanmougin (ENS Paris, France)
Théotime Grohens (ENS Paris, France)

Winners of
            the 2014 edition of the Hash Code

Hash Code 2014

Anael Bonneton (ENSIMAG, France)
Basile Clement (ENS Paris, France)
Kenji Maillard (ENS Paris, France)
Ulysse Beaugnon (ENS Paris, France)