Challenge

Select a cycle type to start!

Graph Parameters

Parameters

Graph Info

Vertices: 6

Edges: 0

Degree sequence: -

Cycle Types

Hamiltonian Cycle

• Visits each vertex exactly once

• Returns to starting vertex

• NP-complete problem

Eulerian Cycle

• Traverses each edge exactly once

• Returns to starting vertex

• Exists if all vertices have even degree

TSP Cycle

• Shortest Hamiltonian cycle

• Minimizes total edge weight

• NP-hard optimization problem

Hamiltonian Cycle

A Hamiltonian cycle visits every vertex exactly once and returns to the starting vertex.

Properties:

  • Uses exactly n edges for n vertices
  • Each vertex has degree 2 in the cycle
  • Finding one is NP-complete

Necessary conditions:

For a graph to have a Hamiltonian cycle, it must be connected and typically needs high vertex connectivity.

Eulerian Cycle

An Eulerian cycle traverses every edge exactly once and returns to the starting vertex.

Euler's Theorem:

A connected graph has an Eulerian cycle if and only if every vertex has even degree.

Algorithm:

Hierholzer's algorithm can find an Eulerian cycle in O(E) time when one exists.

TSP Cycle

The Traveling Salesperson Problem finds the shortest Hamiltonian cycle.

Optimization:

Among all Hamiltonian cycles, find the one with minimum total weight.

Complexity:

NP-hard problem. Approximation algorithms and heuristics are used for large instances.