1 phone conversation about resume and past experience.

1 lunch conversation about past experience and areas/features the applicant would like to improve or contribute to any of Valve's products (from both technical and business perspectives).

Full day of on-site interviews:

• 3 design/coding sessions
• 1 session about a general topic outside of the candidate's comfort/experience zone
• 1 lunch conversation about general technical/business thinking, aptitude, and customer focus

• Implement itoa, i.e., convert integer to string.

• Design an elevator. How would you decide where the elevator should stop, go next, etc.?

• Design/implement a simple calculator (simple display, 1 key press at a time, state machine).

• Compute the distance between 2 axis-aligned rectangles. The distance is defined such that it is:

  1. Zero if both rectangles intersect.
  2. The vertical/horizontal distance between the edges in case they're adjacent or on top of each other.
  3. The Euclidean distance between the corners otherwise.

• How would you devise a scoring function for players' performance in a game like Counter-Strike?