무방향 그래프의 연결된 구성 요소를 찾는 C++ 프로그램

주어진 무방향 그래프에 대한 Weakly 또는 Strongly Connected는 DFS를 사용하여 찾을 수 있습니다. 이 문제의 C++ 프로그램입니다.

사용된 기능

Begin
Function fillorder() = fill stack with all the vertices.
   a) Mark the current node as visited and print it
   b) Recur for all the vertices adjacent to this vertex
   c) All vertices reachable from v are processed by now, push v to Stack
End
Begin
Function DFS() :
   a) Mark the current node as visited and print it
   b) Recur for all the vertices adjacent to this vertex
End

예시

#include <iostream>
#include <list>
#include <stack>
using namespace std;
class G {
   int m;
   list<int> *adj;
   //declaration of functions
   void fillOrder(int n, bool visited[], stack<int> &Stack);
   void DFS(int n, bool visited[]);
   public:
      G(int N); //constructor
      void addEd(int v, int w);
      int print();
      G getTranspose();
};
G::G(int m) {
   this->m = m;
   adj = new list<int> [m];
}
void G::DFS(int n, bool visited[]) {
   visited[n] = true; // Mark the current node as visited and print it
   cout << n << " ";
   list<int>::iterator i;
   //Recur for all the vertices adjacent to this vertex
   for (i = adj[n].begin(); i != adj[n].end(); ++i)
      if (!visited[*i])
         DFS(*i, visited);
}
G G::getTranspose() {
   G g(m);
   for (int n = 0; n< m; n++) {
      list<int>::iterator i;
      for (i = adj[n].begin(); i != adj[n].end(); ++i) {
         g.adj[*i].push_back(n);
      }
   }
   return g;
}
void G::addEd(int v, int w) {
   adj[v].push_back(w); //add w to v's list
}
void G::fillOrder(int v, bool visited[], stack<int> &Stack) {
   visited[v] = true; //Mark the current node as visited and print it
   list<int>::iterator i;
   //Recur for all the vertices adjacent to this vertex
   for (i = adj[v].begin(); i != adj[v].end(); ++i)
      if (!visited[*i])
         fillOrder(*i, visited, Stack);
         Stack.push(v);
}
int G::print() { //print the solution
   stack<int> Stack;
   bool *visited = new bool[m];
   for (int i = 0; i < m; i++)
      visited[i] = false;
      for (int i = 0; i < m; i++)
         if (visited[i] == false)
            fillOrder(i, visited, Stack);
   G graph= getTranspose(); //Create a reversed graph
   for (int i = 0; i < m; i++) //Mark all the vertices as not visited
      visited[i] = false;
   int count = 0;
   //now process all vertices in order defined by Stack
   while (Stack.empty() == false) {
      int v = Stack.top();
      Stack.pop(); //pop vertex from stack
      if (visited[v] == false) {
         graph.DFS(v, visited);
         cout << endl;
      }
      count++;
   }
   return count;
}
int main() {
   G g(5);
   g.addEd(2, 1);
   g.addEd(3, 2);
   g.addEd(1, 0);
   g.addEd(0, 3);
   g.addEd(3, 1);
   cout << "Following are strongly connected components
   in given graph \n";
   if (g.print() > 1) {
      cout << "Graph is weakly connected.";
   } else {
      cout << "Graph is strongly connected.";
   }
   return 0;
}

출력

Following are strongly connected components in given
graph
4
0 1 2 3
Graph is weakly connected.