# fn()dijkstraComputes shortest paths from a single source in a graph.

Defined in ```void dijkstra(predecessor, distance, g, source, weight); ```

## Parameters

 `predecessor` A property map. A property map that represents predecessor relationships among vertices. It determines a shortest-paths tree. A property map.Indicates for each vertex the distance from the source. A graph. Types: Directed Graph A source vertex. Types: VertexDescriptor A weight map. A property map with edge weights. Edge weights have to be nonnegative.

## Detailed Description

### Remarks

Edge weights have to be nonnegative.

### 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 10 directed edges (0,1), (0,3), ...
TSize numEdges = 10;
TVertexDescriptor edges[] = {0, 1, 0, 3, 1, 2, 1, 3, 2, 4, 3, 1, 3, 2, 3, 4, 4, 0, 4, 2};
TGraph g;
addEdges(g, edges, numEdges);

// Fill external edge weight map.
unsigned weights[] = {10, 5, 1, 2, 4, 3, 9, 2, 7, 6};
String<unsigned> weightMap;
assignEdgeMap(weightMap, g, weights);

// Run Dijkstra's algorithm from vertex 0.
String<unsigned> predMap;
String<unsigned> distMap;
dijkstra(predMap, distMap, g, 0, weightMap);

// Print results to stdout.
std::cout << "Single-Source Shortest Paths: \n";
typedef Iterator<TGraph, VertexIterator>::Type TVertexIterator;
TVertexIterator it(g);
while (!atEnd(it))
{
std::cout << "Path from 0 to " << getValue(it) << ": ";
_printPath(g, predMap, (TVertexDescriptor) 0, getValue(it));
std::cout << " (Distance: " << getProperty(distMap, getValue(it)) << ")\n";
goNext(it);
}

// We can achieve the same thing using an internal map that is edge cargos.
typedef unsigned int TEdgeCargo;
typedef Directed<TEdgeCargo> TEdges;
typedef Graph<TEdges> TCargoGraph;

// Construct graph with the same edges as above.
TCargoGraph cargoG;
addEdges(cargoG, edges, numEdges);

// Fill internal edge weight map.
InternalPropertyMap<TEdgeCargo> intMap;
assignEdgeMap(intMap, cargoG, weights);

// Run Dijkstra's algorithm from vertex 0.
clear(predMap);
clear(distMap);
dijkstra(predMap, distMap, cargoG, 0, intMap);

// Print result to stdout.
std::cout << "\nSingle-Source Shortest Paths: \n";
typedef Iterator<TCargoGraph, VertexIterator>::Type TCargoVertexIterator;
TCargoVertexIterator itC(cargoG);
while (!atEnd(itC))
{
std::cout << "Path from 0 to " << getValue(itC) << ": ";
_printPath(g, predMap, (TVertexDescriptor)0, getValue(itC));
std::cout << " (Distance: " << getProperty(distMap, getValue(itC)) << ")\n";
goNext(itC);
}

return 0;
}
```
```Single-Source Shortest Paths:
Path from 0 to 0: 0 (Distance: 0)
Path from 0 to 1: 0,3,1 (Distance: 8)
Path from 0 to 2: 0,3,1,2 (Distance: 9)
Path from 0 to 3: 0,3 (Distance: 5)
Path from 0 to 4: 0,3,4 (Distance: 7)

Single-Source Shortest Paths:
Path from 0 to 0: 0 (Distance: 0)
Path from 0 to 1: 0,3,1 (Distance: 8)
Path from 0 to 2: 0,3,1,2 (Distance: 9)
Path from 0 to 3: 0,3 (Distance: 5)
Path from 0 to 4: 0,3,4 (Distance: 7)
```

## Data Races

If not stated otherwise, concurrent invocation is not guaranteed to be thread-safe.