OCR MEI D2 2012 June — Question 3

Exam BoardOCR MEI
ModuleD2 (Decision Mathematics 2)
Year2012
SessionJune
TopicTravelling Salesman

3 The weights on the network represent distances.
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  1. The answer book shows the initial tables and the results of iterations \(1,2,3\) and 5 when Floyd's algorithm is applied to the network.
    (A) Complete the two tables for iteration 4.
    (B) Use the final route table to give the shortest route from vertex \(\mathbf { 3 }\) to vertex \(\mathbf { 5 }\).
    (C) Use the final distance table to produce a complete network with weights representing the shortest distances between vertices.
  2. Using the complete network of shortest distances, find a lower bound for the solution to the Travelling Salesperson Problem by deleting vertex 5 and its arcs, and by finding the length of a minimum connector for the remainder. (You may find the minimum connector by inspection.)
  3. Use the nearest neighbour algorithm, starting at vertex \(\mathbf { 1 }\), to produce a Hamilton cycle in the complete network. Give the length of your cycle.
  4. Interpret your Hamilton cycle in part (iii) in terms of the original network.
  5. Give a walk of minimum length which traverses every arc on the original network at least once, and which returns to the start. Give the length of your walk.