This problem is known as travelling self-person problem. We have a travelling self-person who wants to visit a given set of cities and he would like to find the tour of minimum cost. For instance, the cost could be the number of kilometres that he has to travel or the number of litres that he has to spend to perform the tour. Of course, he would like to follow the minimum cost tour. The problem can be formulated as follows. We have a complete graph G and we have a weight function on edges. The solution is a tour of this graph, that is a permutation of the nodes of the graph. And the measure is the cost of the tour, that is the sum of the edges of we should travel if we follow the permutation.

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