57 lines
1.6 KiB
Markdown
57 lines
1.6 KiB
Markdown
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Finding all the elementary circuits of a directed graph
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Algorithm by D. B. Johnson
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Finding all the elementary circuits of a directed graph.
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D. B. Johnson, SIAM Journal on Computing 4, no. 1, 77-84, 1975.
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http://dx.doi.org/10.1137/0204007
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Functional and iterative version.
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Additional code available at http://mancoosi.org/~abate/finding-all-elementary-circuits-directed-graph
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Original git repository at http://mancoosi.org/~abate/repos/cycles.git
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The original code was faulty. This version is fixed for the functional as well
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as the iterative version.
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Usage
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-----
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make
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./cycles_{iter,functional}.native 4 0,1 0,2 1,0 1,3 2,0 3,0 3,1 3,2
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First argument is the number of vertices. Subsequent arguments are ordered
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pairs of comma separated vertices that make up the directed edges of the
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graph.
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DOT file input
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--------------
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For simplicity, there is no DOT file parser included but the following allows
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to create a suitable argument string for simple DOT graphs.
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Given a DOT file of a simple (no labels, colors, styles, only pairs of
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vertices...) directed graph, the following line produces commandline
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arguments in the above format for that graph.
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echo `sed -n -e '/^\s*[0-9]\+;$/p' graph.dot | wc -l` `sed -n -e 's/^\s*\([0-9]\) -> \([0-9]\);$/\1,\2/p' graph.dot`
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The above line works on DOT files like the following:
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digraph G {
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0;
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1;
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2;
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0 -> 1;
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0 -> 2;
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1 -> 0;
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2 -> 0;
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2 -> 1;
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}
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It would produce the following output:
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3 0,1 0,2 1,0 2,0 2,1
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