Let 𝐺 be an undirected complete graph on 𝑛 vertices, where 𝑛 > 2. Then, the number of different Hamiltonian cycles in 𝐺 is equal to

Q. Let 𝐺 be an undirected complete graph on 𝑛 vertices, where 𝑛 > 2. Then, the number of different Hamiltonian cycles in 𝐺 is equal to

Ans: Option D

Solution:

A simple circuit in a graph G that passes through every vertex exactly once is called a Hamiltonian circuit. In Hamiltonian cycle is a Hamiltonian circuit in which initial and final vertex are same. In an undirected complete graph on n vertices, there are n permutations are possible to visit every node. But from these permutations, there are: n different places (i.e., nodes) you can start; two (clockwise or anticlockwise) different directions you can travel. So, any one of these n! cycles is in a set of 2n cycles which all contain the same set of edges.

So, there are =

distinct Hamilton cycles.