Summary of the San Franscisco routes example in depth-first, breadth-first best-first, and A* search -- Step 3

The starting state is Monterey and the only goal state is San Francisco.

The evaluation function values (measured as straight-line distance to San Francisco): Monterey: 100; Santa Cruz: 65; Gilroy: 74; San Jose: 45; San Francisco: 0; Oakland: 15.

The costs between states (measured as road distance in miles): Monterey to Santa Cruz, 45; Monterey to Gilroy, 35; Santa Cruz to San Jose, 30; Gilroy to San Jose, 35; Santa Cruz to San Francisco, 85; San Jose to San Francisco, 50; San Jose to Oakland, 50; Oakland to San Francisco, 20.

The working data structure for depth-first is a stack where items are added and removed only at the front; for breadth, a queue where items are added at the rear and removed from the front; for best-first and A*, a set of items where the lowest-value item is chosen at each step. The argument after the state name is the backpointer, and the number after that in best-first and A* is the evaluation of the state.

Search methodStates visitedAgendaSolution path
Depth-first searchMontereyStack top: San Francisco
Santa CruzStack item 2:Santa Cruz
Stack item 3: Monterey
Breadth-first searchMonterey (-)Queue front: Gilroy (Monterey)
Santa Cruz (Monterey)Queue item 2: San Francisco (Santa Cruz)
Queue item 3: San Jose (Santa Cruz)
Best-first searchMonterey (-, 100)Set item: Gilroy (Monterey, 74)
Santa Cruz (Monterey, 65)Set item: San Francisco (Santa Cruz, 0)
Set item: San Jose (Santa Cruz, 45)
A* searchMonterey (_, 100)Set item: Santa Cruz (Monterey, 110)
Gilroy (Monterey, 109)Set item: San Jose (Gilroy, 115)

Click here to see the next step with each of the four searches.