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1 | // -*- c++ -*- |
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2 | #ifndef HUGO_DIMACS_H |
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3 | #define HUGO_DIMACS_H |
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4 | |
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5 | #include <iostream> |
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6 | #include <string> |
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7 | #include <vector> |
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8 | |
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9 | /// \file \brief Dimacs file format reader. |
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10 | |
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11 | namespace hugo { |
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12 | |
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13 | /// Dimacs flow file format reader function. |
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14 | |
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15 | /// This function reads a flow instance from dimacs flow format. |
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16 | /// At the beginning \c g is cleared by \c g.clear(). |
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17 | /// If the data coming from \c is is a max flow problem instance, then |
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18 | /// \c s and \c t will be respectively the source and target nodes |
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19 | /// and \c capacity will contain the edge capacities. |
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20 | /// If the data is a shortest path problem instance then \c s will be the |
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21 | /// source node and \c capacity will contain the edge lengths. |
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22 | template<typename Graph, typename CapacityMap> |
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23 | void readDimacsMaxFlow(std::istream& is, Graph &g, typename Graph::Node &s, typename Graph::Node &t, CapacityMap& capacity) { |
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24 | g.clear(); |
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25 | int cap; |
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26 | char d; |
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27 | std::string problem; |
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28 | char c; |
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29 | int i, j; |
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30 | std::string str; |
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31 | int n, m; |
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32 | typename Graph::Edge e; |
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33 | std::vector<typename Graph::Node> nodes; |
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34 | while (is>>c) { |
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35 | switch (c) { |
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36 | case 'c': //comment |
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37 | getline(is, str); |
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38 | break; |
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39 | case 'p': //problem definition |
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40 | is >> problem >> n >> m; |
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41 | getline(is, str); |
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42 | nodes.resize(n+1); |
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43 | for (int k=1; k<=n; ++k) nodes[k]=g.addNode(); |
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44 | break; |
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45 | case 'n': //node definition |
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46 | if (problem=="sp") { //shortest path problem |
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47 | is >> i; |
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48 | getline(is, str); |
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49 | s=nodes[i]; |
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50 | } |
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51 | if (problem=="max") { //max flow problem |
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52 | is >> i >> d; |
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53 | getline(is, str); |
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54 | if (d=='s') s=nodes[i]; |
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55 | if (d=='t') t=nodes[i]; |
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56 | } |
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57 | break; |
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58 | case 'a': |
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59 | is >> i >> j >> cap; |
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60 | getline(is, str); |
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61 | e=g.addEdge(nodes[i], nodes[j]); |
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62 | capacity.update(); |
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63 | capacity.set(e, cap); |
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64 | break; |
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65 | } |
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66 | } |
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67 | } |
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68 | |
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69 | } //namespace hugo |
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70 | |
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71 | #endif //HUGO_DIMACS_H |
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