Given a graph and a node in it as the starting point, the traveling salesman problem (TSP) is about finding a least cost path that starts and ends at the starting node, and goes through each other node in the graph once and exactly once. The edges of the graph are labeled by a number representing the cost of traveling between the connecting two nodes. Formulate this problem as a search problem by specifying the states, possible initial states, goal test, operators, and operator costs.