fn() topologicalSortPerforms a topological sort on a directed acyclic graph (DAG).
Performs a topological sort on a directed acyclic graph (DAG).
Defined in | <seqan/graph_algorithms.h> |
---|---|
Signature |
void topologicalSort(topSort, g);
|
Parameters
topSort
|
A topological ordering of the vertices. Types: String. |
---|---|
g
|
A directed acyclic graph. Types: Directed Graph |
Detailed Description
A topological sort is a linear ordering of all its vertices such that if the graph contains an edge (u,v) then u appears before v in the ordering.
Example
#include <iostream>
#include <seqan/graph_algorithms.h>
using namespace seqan;
int main()
{
typedef Graph<Directed<> > TGraph;
typedef VertexDescriptor<TGraph>::Type TVertexDescriptor;
typedef Size<TGraph>::Type TSize;
// Create graph with 9 directed edges (0,3), (0,1), ...
TSize numEdges = 9;
TVertexDescriptor edges[] = {0, 3, 0, 1, 1, 2, 3, 2, 5, 7, 5, 6, 6, 7, 6, 3, 8, 7};
TGraph g;
addEdges(g, edges, numEdges);
// Print graph.
std::cout << g << "\n";
// Create external property map with vertex labels.
String<std::string> nameMap;
std::string names[] = {"shirt", "tie", "jacket", "belt", "watch", "undershorts", "pants", "shoes", "socks"};
assignVertexMap(nameMap, g, names);
// Get vertex descriptor in topological sort order.
String<TVertexDescriptor> order;
topologicalSort(order, g);
// Write the result to stdout.
std::cout << "Topological sort: \n";
typedef Iterator<String<TVertexDescriptor> >::Type TStringIterator;
TStringIterator it = begin(order);
TStringIterator itEnd = end(order);
while (it != itEnd)
{
std::cout << getProperty(nameMap, getValue(it)) << ",";
goNext(it);
}
std::cout << "\n";
return 0;
}
Adjacency list: 0 -> 1,3, 1 -> 2, 2 -> 3 -> 2, 4 -> 5 -> 6,7, 6 -> 3,7, 7 -> 8 -> 7, Edge list: Source: 0,Target: 1 (Id: 1) Source: 0,Target: 3 (Id: 0) Source: 1,Target: 2 (Id: 2) Source: 3,Target: 2 (Id: 3) Source: 5,Target: 6 (Id: 5) Source: 5,Target: 7 (Id: 4) Source: 6,Target: 3 (Id: 7) Source: 6,Target: 7 (Id: 6) Source: 8,Target: 7 (Id: 8) Topological sort: socks,undershorts,pants,shoes,watch,shirt,belt,tie,jacket,
Data Races
If not stated otherwise, concurrent invocation is not guaranteed to be thread-safe.