Line | |
---|

1 | // -*- c++ -*- |
---|

2 | #ifndef HUGO_DIMACS_H |
---|

3 | #define HUGO_DIMACS_H |
---|

4 | |
---|

5 | #include <iostream> |
---|

6 | #include <string> |
---|

7 | #include <vector> |
---|

8 | |
---|

9 | /// \file |
---|

10 | /// \brief Dimacs file format reader. |
---|

11 | |
---|

12 | namespace hugo { |
---|

13 | |
---|

14 | /// Dimacs flow file format reader function. |
---|

15 | |
---|

16 | /// This function reads a flow instance from dimacs flow format. |
---|

17 | /// At the beginning \c g is cleared by \c g.clear(). |
---|

18 | /// If the data coming from \c is is a max flow problem instance, then |
---|

19 | /// \c s and \c t will be respectively the source and target nodes |
---|

20 | /// and \c capacity will contain the edge capacities. |
---|

21 | /// If the data is a shortest path problem instance then \c s will be the |
---|

22 | /// source node and \c capacity will contain the edge lengths. |
---|

23 | template<typename Graph, typename CapacityMap> |
---|

24 | void readDimacsMaxFlow(std::istream& is, Graph &g, typename Graph::Node &s, typename Graph::Node &t, CapacityMap& capacity) { |
---|

25 | g.clear(); |
---|

26 | int cap; |
---|

27 | char d; |
---|

28 | std::string problem; |
---|

29 | char c; |
---|

30 | int i, j; |
---|

31 | std::string str; |
---|

32 | int n, m; |
---|

33 | typename Graph::Edge e; |
---|

34 | std::vector<typename Graph::Node> nodes; |
---|

35 | while (is>>c) { |
---|

36 | switch (c) { |
---|

37 | case 'c': //comment |
---|

38 | getline(is, str); |
---|

39 | break; |
---|

40 | case 'p': //problem definition |
---|

41 | is >> problem >> n >> m; |
---|

42 | getline(is, str); |
---|

43 | nodes.resize(n+1); |
---|

44 | for (int k=1; k<=n; ++k) nodes[k]=g.addNode(); |
---|

45 | break; |
---|

46 | case 'n': //node definition |
---|

47 | if (problem=="sp") { //shortest path problem |
---|

48 | is >> i; |
---|

49 | getline(is, str); |
---|

50 | s=nodes[i]; |
---|

51 | } |
---|

52 | if (problem=="max") { //max flow problem |
---|

53 | is >> i >> d; |
---|

54 | getline(is, str); |
---|

55 | if (d=='s') s=nodes[i]; |
---|

56 | if (d=='t') t=nodes[i]; |
---|

57 | } |
---|

58 | break; |
---|

59 | case 'a': |
---|

60 | is >> i >> j >> cap; |
---|

61 | getline(is, str); |
---|

62 | e=g.addEdge(nodes[i], nodes[j]); |
---|

63 | capacity.update(); |
---|

64 | capacity.set(e, cap); |
---|

65 | break; |
---|

66 | } |
---|

67 | } |
---|

68 | } |
---|

69 | |
---|

70 | } //namespace hugo |
---|

71 | |
---|

72 | #endif //HUGO_DIMACS_H |
---|

**Note:** See

TracBrowser
for help on using the repository browser.