Traveling salesman problem (large) The code implemets a heuristic for the TSP, rather than an exact algorithm, and as a result will be able to handle much larger problem sizes.
The first line indicates the number of cities. Each city is a point in the plane, and each subsequent line indicates the x- and y-coordinates of a single city.
the nearest neighbor heuristic:
Start the tour at the first city. Repeatedly visit the closest city that the tour hasn't visited yet. In case of a tie, go to the closest city with the lowest index. For example, if both the third and fifth cities have the same distance from the first city (and are closer than any other city), then the tour should begin by going from the first city to the third city. Once every city has been visited exactly once, return to the first city to complete the tour.