## Great people. Great product. Great place to build your future!

yuilop is looking for a Lead Server Core Developer that will help us change the way the world communicates.

If you are passionate about writing server code and being part of an creative and international team this is your opportunity!

Job Responsibilities

• Write logical, simple and performance oriented code in Java or Erlang
• Build unit tests and performance test driven code
• Code towards a zero maintenance system

Job Requirements

• BS in computer science or Computer Information Systems, or equivalent. MS or PhD is a plus
• 3/4 years of strong Java or Erlang programming and debugging skills
• Knowledge of TCP/IP – UDP/IP and experience with network programming
• Proficiency on XMPP
• Knowledge with Key-Value Databases
• Knowledge with SQL storage
• Experience building and scaling distributed, highly available systems

Bonus Points

• You are a contributor to open source projects and like “hacker culture”
• You have experience or background in system administration, security and operations

Fast & Functions Challenge (Java or Erlang)

Write code that implements the described functions to be executed as fast as possible:

• Build a function that given a list of Integers in the range [-65000,65000], the function

returns true if any subset of the list summed is equal to zero. False otherwise.

Example:

■ [0, 1, 2, -3] returns true. As 1+2+(-3)==0.

■ [1, 2, 3, -8] returns false. As no subset summed is equal 0.

■ [1, 4, 5, 2, -3] returns true.

• Build a function that given a list of Integers pairs in the range [-65000,65000], that represents {X, Y} Coordinates in a Plane. The function returns the two closest pairs.

○ Example:

■ [{0,0}, {1,20}, {5, 2}] returns [{0,0}, {5, 2}]

■ [{-10,10}, {1,5}, {4, 3}] returns [{1,5}, {4, 3}]

Start date: ASAP
Location: Barcelona – First Mobile World Capital!
Offer: We offer creative freedom, competitive salary including employee stock option program, as well as fun work environment in Barcelona city center with a fruit stocked kitchen and more.