











• 
Recall:




– 
BestFirst Search
with f(n) = g(n) + h(n) is A*




– 
A* finds optimal
solution if h(n) never



overestimates




– 
A*’s serious
limitation: memory requirement (often


exponential)




– 
A*’s second
limitation: keeping candidate nodes



sorted (O(log N)
per node, N number of nodes)

