Best-First Search

• Initialize priority queue (e.g. a heap)
  • Initialization includes an evaluation function to determine priority
• Add an initial candidate to the heap
  • This includes a number derived from the evaluation function
• Initialize visited candidate set
• Loop Forever
  • Remove the top of the heap
    • If the heap 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 heap
    • Each candidate is prioritized by using the evaluation function