Example Program
Kruskals Algorithm
Kruskal's algorithm for computing a minimum spanning tree.
File "graph_algo_tree_kruskal.cpp"
A tutorial about kruskal's algorithm

1 | #include <iostream>
2 | #include <seqan/graph_algorithms.h>
3 |
4 | using namespace seqan;
5 |
6 |
7 | int main() {
8 | typedef Graph<Undirected<> > TGraph;
9 | typedef VertexDescriptor<TGraph>::Type TVertexDescriptor;
10 | typedef EdgeDescriptor<TGraph>::Type TEdgeDescriptor;
11 | typedef Size<TGraph>::Type TSize;

Graph creation: 14 undirected edges {0,1}, {0,6}, ...

12 | TSize numEdges = 14;
13 | TVertexDescriptor edges[] = {0,1, 0,6, 1,2, 1,6, 2,3, 2,4, 2,8, 3,5, 3,8, 4,6, 4,7, 5,8, 6,7, 7,8};
14 | TGraph g;
15 | addEdges(g,edges, numEdges);
16 | ::std::cout << g << std::endl;

Two external property maps: Weight and vertex names

17 | unsigned int weights[] = {4, 8, 8, 11, 7, 2, 4, 9, 14, 7, 6, 10, 1, 2 };
18 | char names[] = {'a', 'b', 'c', 'd', 'i', 'e', 'h', 'g', 'f'};
19 | String<int> weightMap;
20 | resizeEdgeMap(g, weightMap, weights);
21 | String<char> nameMap;
22 | resizeVertexMap(g,nameMap, names);

Out-parameter: Selected tree edges

23 | String<TVertexDescriptor> treeEdges;

Kruskal's algorithm

24 | kruskalsAlgorithm(g, 0, weightMap, treeEdges);

Console output

25 | ::std::cout << "Minimum Spanning Tree (Kruskal's algorithm): " << ::std::endl;
26 | ::std::cout << "Tree Edges: ";
27 | typedef Iterator<String<TVertexDescriptor> >::Type TStrIterator;
28 | TStrIterator it = begin(treeEdges);
29 | TStrIterator itEnd = end(treeEdges);
30 | while(it!=itEnd) {
31 | ::std::cout << "(" << getProperty(nameMap,getValue(it)) << ",";
32 | goNext(it);
33 | ::std::cout << getProperty(nameMap,getValue(it)) << "), ";
34 | goNext(it);
35 | }
36 | ::std::cout << ::std::endl;
37 | return 0;
38 | }

See
Graph, kruskalsAlgorithm
SeqAn - Sequence Analysis Library - www.seqan.de

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