Figure of the algorithm series--BFS

The breadth-first search takes the source node s as the starting point, and the algorithm always extends the boundary between the discovered and the uncovered nodes, extending outward along its breadth direction. That is, the algorithm needs to discover all the nodes that are from the source node S K to find other nodes that are k+1 from the source node.

Talk is cheap,show me the code! on the specific code, the easiest to explain it all.

This example is based on an no-map, and the comments in the code are specified and are not explained in each step:

1#include <iostream>2#include <list>3#include <queue>4 using namespacestd;5 6 //graph without Direction7 classgraph{8 Private:9     intV//number of nodes in the graphTenlist<int> *adj;//point to an array that contains a list of pro links One  Public: AGraph (intv); -     voidAddedge (intStartintEnd);//add a pro edge -     voidBFS (ints);//Breadth First Search the }; -  -Graph::graph (intv) { -      This->v =v; +Adj =Newlist<int>[v]; - } +  A //add an edge to the No map add two items to the Pro table at voidGraph::addedge (intStartintend) { - adj[start].push_back (end); - adj[end].push_back (start); - } -  - voidGRAPH::BFS (ints) { in     //mark all nodes first without being accessed. -     BOOL* visited =New BOOL[v]; to      for(intI=0; i<v;i++) +Visited[i] =false; -     //Create a queue thequeue<int> q = queue<int>(); *     //set source node first $Visited[s] =true;Panax Notoginseng Q.push (s); -  the      while(!Q.empty ()) { +         intnode =Q.front (); Acout<<node<<" "; the Q.pop (); +         //node node's pro table -list<int> nlist =Adj[node]; $list<int>::iterator Beg =Nlist.begin (); $          for(; Beg! = Nlist.end (); beg++){             -             if(!visited[*Beg]) { -Visited[*beg] =true; theQ.push (*beg); -             }Wuyi         } the     } -cout<<"\ n"; Wu } -  About intMain () { $Graph G = Graph (6); -G.addedge (0,1); -G.addedge (0,2); -G.addedge (0,5); AG.addedge (1,3); +G.addedge (2,3); theG.addedge (2,5); -G.addedge (2,4); $G.addedge (4,5); theG.BFS (0); the  the     return 0; the}

Each node in this example is represented by an integer and, more complicated, each node can be organized into a node structure, which can add a distance attribute to each node node.

The results of the operation are as follows:

Figure of the algorithm series--BFS