Breadth-First Search

• Initialize FIFO queue; add an initial candidate to it
• Initialize visited candidate set
• Loop Forever
  • Remove the head of the queue
    • If the queue is empty, quit with failure
    • If the candidate has been visited, skip the rest of the inner loop
    • If not, add the candidate to the visited set
  • Evaluate the candidate
  • If the candidate is a solution, quit and return it
  • Otherwise:
    • Generate some new candidates from the candidate
    • Add the new candidates to the end of the queue