There is almost exactly the same question. But I still don't understand, how is this heuristic working and in what sequence vertexes are passed through. Also there is a picture in a book: enter image description here

That shows comparison of nearest-neghbor heuristic and what I believe is a closest-pair heuristic. From the picture I may assume that on the top picture, 0 point was selected first, but on the bottom picture there was selected the leftmost or the rightmost one. Because there is nothing said about first point selection (also the closest-pair heuristic doesn't do any actions in that), I may assume that any algorithm results however good it is won't give you the bottom picture if it doesn't consider, what point to start with.

For now I just want to know, what steps closest-pair heuristic makes. A picture similar to the bottom one with numbers associated with each iteration along with explanation would be appreciated.

Here is the link to the book taken from that post.

Edit
Report