Decreasing agenda size
Agenda size can be problematic in a best first search
- for a branching factor b, agenda grows to size O(bk) after k checks
- inserting b elements into the agenda after k checks is O(b logb+b logk)
Immediate successors of an assignment are totally ordered
- non-least cost successors only checked after least cost successor
Insert only least cost successor onto agenda Sort remaining successors Each assignment has exactly two successors
- least cost immediate successor
- next more expensive sibling
Size of the agenda is bounded by the number of checks
- inserting b successors after k checks is O(b logb + 2logk)