Hamiltonian path
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A game…..
The figure has 20 red
dots. Can you draw a
path that visits each
vertex (Dots) exactly
once????
Try it out….
Solution!!!
Icosian game developed by William Rowan Hamilton
Hamiltonian path
• In the mathematical field of graph theory, a Hamiltonian path
(or traceable path) is a path in an undirected or directed graph
that visits each vertex exactly once.
A Hamiltonian cycle in a dodecahedron
Some definitions….
• A Hamiltonian path or traceable path is a path that visits each
vertex exactly once.
• A graph that contains a Hamiltonian path is called a traceable
graph.
• A graph is Hamiltonian-connected if for every pair of vertices
there is a Hamiltonian path between the two vertices.
• A Hamiltonian cycle, Hamiltonian circuit, vertex tour or graph
cycle is a cycle that visits each vertex exactly once (except for
the vertex that is both the start and end, which is visited
twice).
• A graph that contains a Hamiltonian cycle is called a
Hamiltonian graph.
Hamiltonian path problem
• Hamiltonian path problem and the Hamiltonian cycle problem
are problems of determining whether a Hamiltonian path (a
path in an undirected or directed graph that visits each vertex
exactly once) or a Hamiltonian cycle exists in a given graph
(whether directed or undirected).
Algorithms for solving the problem
• Brute-force search algorithm
There are n! different sequences of vertices that might be
Hamiltonian paths in a given n-vertex graph (and are, in a
complete graph), so a brute force search algorithm that tests all
possible sequences would be very slow. There are several faster
approaches.
• Inclusion–exclusion principle
• Dynamic programming algorithm
• Frank Rubin method
• Monte Carlo algorithm
Usingunconventional models of computing
• Because of the difficulty of solving the Hamiltonian path and
cycle problems on conventional computers, they have also
been studied in unconventional models of computing. For
instance, Leonard Adleman showed that the Hamiltonian path
problem may be solved using a DNA computer.
• Exploiting the parallelism inherent in chemical reactions, the
problem may be solved using a number of chemical reaction
steps linear in the number of vertices of the graph; however, it
requires a factorial number of DNA molecules to participate in
the reaction.
ag1805x

Hamiltonian path

  • 1.
  • 2.
    A game….. The figurehas 20 red dots. Can you draw a path that visits each vertex (Dots) exactly once???? Try it out….
  • 3.
    Solution!!! Icosian game developedby William Rowan Hamilton
  • 4.
    Hamiltonian path • Inthe mathematical field of graph theory, a Hamiltonian path (or traceable path) is a path in an undirected or directed graph that visits each vertex exactly once. A Hamiltonian cycle in a dodecahedron
  • 5.
    Some definitions…. • AHamiltonian path or traceable path is a path that visits each vertex exactly once. • A graph that contains a Hamiltonian path is called a traceable graph. • A graph is Hamiltonian-connected if for every pair of vertices there is a Hamiltonian path between the two vertices. • A Hamiltonian cycle, Hamiltonian circuit, vertex tour or graph cycle is a cycle that visits each vertex exactly once (except for the vertex that is both the start and end, which is visited twice). • A graph that contains a Hamiltonian cycle is called a Hamiltonian graph.
  • 6.
    Hamiltonian path problem •Hamiltonian path problem and the Hamiltonian cycle problem are problems of determining whether a Hamiltonian path (a path in an undirected or directed graph that visits each vertex exactly once) or a Hamiltonian cycle exists in a given graph (whether directed or undirected).
  • 7.
    Algorithms for solvingthe problem • Brute-force search algorithm There are n! different sequences of vertices that might be Hamiltonian paths in a given n-vertex graph (and are, in a complete graph), so a brute force search algorithm that tests all possible sequences would be very slow. There are several faster approaches. • Inclusion–exclusion principle • Dynamic programming algorithm • Frank Rubin method • Monte Carlo algorithm
  • 8.
    Usingunconventional models ofcomputing • Because of the difficulty of solving the Hamiltonian path and cycle problems on conventional computers, they have also been studied in unconventional models of computing. For instance, Leonard Adleman showed that the Hamiltonian path problem may be solved using a DNA computer. • Exploiting the parallelism inherent in chemical reactions, the problem may be solved using a number of chemical reaction steps linear in the number of vertices of the graph; however, it requires a factorial number of DNA molecules to participate in the reaction. ag1805x