ABSOLVER is a program which finds functions useful to this algorithm, and Nilsson's sequence and this algorithm can be notably applied to solve the 8-puzzle.  It runs in polynomial time only when its heuristic's error is bounded by the log of the "perfect heuristic," and a similarly named algorithm works when multiple goal states are defined.  Its notable innovation is to use both the sum of two weights and an Open and Closed list when determining which node to examine; it will behave perfectly when its heuristic is exact, and it is only guaranteed to find the optimal solution when the heuristic function is admissible, or strictly less than the actual cost.  Develope
ABSOLVER is a program which finds functions useful to this algorithm, and Nilsson's sequence and this algorithm can be notably applied to solve the 8-puzzle.  It runs in polynomial time only when its heuristic's error is bounded by the log of the "perfect heuristic," and a similarly named algorithm works when multiple goal states are defined.  Its notable innovation is to use both the sum of two weights and an Open and Closed list when determining which node to examine; it will behave perfectly when its heuristic is exact, and it is only guaranteed to find the optimal solution when the heuristic function is admissible, or strictly less than the actual cost.  Developed in 1968 to combine Best First Search and Dijkstra's algorithm, for 10 points, name this search algorithm that finds the shortest path along a graph between two nodes using a distance-plus-cost weighting.
ABSOLVER is a program which finds functions useful to this algorithm, and Nilsson's sequence and this algorithm can be notably applied to solve the 8-puzzle.  
{A} Star