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Text File  |  1994-11-16  |  1.4 KB  |  66 lines
  1. /*******************************************************************************
  2. +
  3. +  LEDA  3.1c
  4. +
  5. +
  6. +  _d.c
  7. +
  8. +
  9. +  Copyright (c) 1994  by  Max-Planck-Institut fuer Informatik
  10. +  Im Stadtwald, 6600 Saarbruecken, FRG     
  11. +  All rights reserved.
  12. + 
  13. *******************************************************************************/
  14.  
  15.  
  16.  
  17. void DIJKSTRA(graph& G, node s, 
  18.               edge_array<int>&  cost, 
  19.               node_array<int>&  dist,
  20.               node_array<edge>& pred,
  21.               priority_queue<node,int>&   PQ)
  22. {
  23.   node_array<pq_item> I(G);
  24.   node v;
  25.                                                                                
  26.   forall_nodes(v,G)
  27.   { pred[v] = nil;
  28.     dist[v] = MAXINT;
  29.    }
  30.  
  31.   dist[s] = 0;
  32.   I[s] = PQ.insert(s,0);
  33.  
  34.   while (! PQ.empty())
  35.   { pq_item it = PQ.find_min();
  36.     node u = PQ.key(it);
  37.     int du = dist[u];
  38.     edge e;
  39.     forall_adj_edges(e,u)
  40.     { v = G.target(e);
  41.       int c = du + cost[e];
  42.       if (c < dist[v])
  43.       { if (dist[v] == MAXINT)
  44.           I[v] = PQ.insert(v,c);
  45.         else
  46.           PQ.decrease_inf(I[v],c);
  47.         dist[v] = c;
  48.         pred[v] = e;
  49.        }                                                                 
  50.      }
  51.     PQ.del_item(it);
  52.    }
  53. }
  54.  
  55.  
  56. void DIJKSTRA(graph& G, node s, 
  57.               edge_array<int>&  cost, 
  58.               node_array<int>&  dist,
  59.               node_array<edge>& pred)
  60. {
  61.   priority_queue<node,int>  PQ;
  62.  
  63.   DIJKSTRA(G,s,cost,dist,pred,PQ);
  64.  
  65.  }
  66.