Question 9
TSP Branch-and-Bound
The TSP Branch-and-Bound algorithm is solving a TSP instance where the cities are A, B, C, .... and so on. The Branch-and-Bound search tree at the time when the algorithm has discovered the optimal tour is shown below.
Each node in the search tree displays an edge (either XY or ~XY), a cost value, and a unique reference number (a1, b1, b2, c1, c2, d1, d2). Use the reference numbers to break ties. When required, enter the reference numbers in short answers.
What information can you glean from the search tree? Answer the sub-questions based on the information gleaned from the search tree.
Determine the number of cities in the TSP instance. Enter the number of cities in the text box, or enter NIL if it is not possible to determine the number of cities.
Enter an integer.
NO SPACES, TABS, DOTS, BRACKETS OR EXTRANEOUS CHARACTERS.
Answer format: 42