Depth First Traversal for a Graph

DFS Directed Graph

Here given code implementation process.

//C Program to find DFS in Directed graph
#include<stdio.h>
#include<stdlib.h>

struct AjlistNode{
    int vId;//Vertices id
    struct AjlistNode*next;
};

struct Graph{
    int data; //node key value
    struct AjlistNode*next;
};
void setData(struct Graph *);
int size; //number of nodes

//set node key value
void setData(struct Graph*node){
    if(node!=NULL && size>0){
        int index=0;
        for(index;index<size;index++){
            //set vertic node data
      node[index].data=index;//set node key
      //Initial no AjlistNode
      //set NULL Value
      node[index].next=NULL;
    }
  }else{
    printf("Vertic Node is Empty");
  }
}
//Add Edge from Two given Nodes
void addEdge(struct Graph*node, int V ,int E){
    //add edge form V to E
    //V and E is Node location
    if(V<size && E <size){
      //first create Adjacency node
        struct AjlistNode *newEdge=(struct AjlistNode*)malloc(sizeof(struct AjlistNode));
        if(newEdge!=NULL){
                        
            newEdge->next=NULL;
            newEdge->vId=E;

            struct AjlistNode *temp=node[V].next;

            if(temp==NULL){
                node[V].next=newEdge;
            }else{
                //Add node at last
                while(temp->next!=NULL){
                    temp=temp->next;
                }      
                temp->next=newEdge;          
            }
        }else{
            printf("\n Memory overflow");
        }
    }else{
        //not valid Vertices
        printf("Invalid Node Vertices %d  %d", V,E);
    }
}
//Display Adjacency list of vertex
void printGraph(struct Graph*node){
    if(node!=NULL){
        struct AjlistNode *temp=NULL;
        for(int index=0;index<size;index++){
            printf("\n Adjacency list of vertex %d  :",index);
            temp=node[index].next;
            while(temp!=NULL){
                //temp->vId is graph node vertices
                //in this case temp->vId is same as 
                //node[temp->vId].data
                
                printf("  %d",node[temp->vId].data);
                temp=temp->next;
            }
        }
    }else{
        printf("Empty Graph");
    }
}

void dfs(int point,int *visit,struct Graph*node){

    if(visit[point]==1){
        return;
    }else{
        visit[point]=1;
        printf("  %d",point);
        struct AjlistNode *temp=node[point].next;
        while(temp!=NULL){
           dfs(temp->vId,visit,node); 
           temp=temp->next;
        }
    }
}
int main(){
    
    size=6;
    struct Graph*node=NULL;


    int *visit=(int*)calloc(size,sizeof(int));

    node=(struct Graph*)malloc(sizeof(struct Graph)*size);
    
    if(node==NULL){
        printf("\n Memory overflow");
    }else{
        //First set node keys
        setData(node); 
        //Connected two node with Edges
        addEdge(node,0,1);
        addEdge(node,0,5);
        addEdge(node,1,1);
        addEdge(node,2,1);
        addEdge(node,3,0);
        addEdge(node,3,3);
        addEdge(node,4,2);
        addEdge(node,4,3);
        addEdge(node,5,1);
        printGraph(node);
        printf(" \n DFS :");
        dfs(4,visit,node);
    }  
    return 0;
}

Output

 Adjacency list of vertex 0  :  1  5
 Adjacency list of vertex 1  :  1
 Adjacency list of vertex 2  :  1
 Adjacency list of vertex 3  :  0  3
 Adjacency list of vertex 4  :  2  3
 Adjacency list of vertex 5  :  1 
 DFS :  4  2  1  3  0  5
//C++ DFS for a directed graph
#include<iostream>
using namespace std;
struct AjlistNode{
    int vId;//Vertices id
    struct AjlistNode*next;
};
struct Vertices{
    int data; //node key value
    struct AjlistNode*next;
};
class Graph{
  Vertices *node;
  int *visit;
  int size;//number of 
public:
    Graph(int);
    void setData();
    void addEdge(int,int);
    void printGraph();
    void dfs(int);
};
Graph::Graph(int size){
    this->size=size;
    //set number of nodes
    node=new Vertices[size];
    
    visit=new int[size];

    for(int index=0;index<size;index++){
        visit[index]=0;
    }
}
//set node key value
void Graph:: setData(){
    if(node!=NULL){
        int index=0;
        for(index;index<size;index++){
            //set vertic node data
      node[index].data=index;//set node key
      //Initial no AjlistNode
      //set NULL Value
      node[index].next=NULL;
    }
  }else{
    cout<<"Vertic Node is Empty"<<endl;
  }
}
//Add Edge from Two given Nodes
void Graph ::addEdge(int V ,int E){
    //add edge form V to E
    //V and E is Node location
    if(V<size && E <size){
      //first create Adjacency node
        AjlistNode *newEdge=new AjlistNode;
        if(newEdge!=NULL){
            
            newEdge->next=NULL;
            newEdge->vId=E;

            AjlistNode *temp=node[V].next;

            if(temp==NULL){
                node[V].next=newEdge;
            }else{
                //Add node at last
                while(temp->next!=NULL){
                    temp=temp->next;
                }      
                temp->next=newEdge;          
            }
        }
    }else{
        //not valid Vertices
        cout<<"Invalid Node Vertices "<< V<<" "<<E;
    }
}
//Display Adjacency list of vertex
void Graph::printGraph(){
    if(node!=NULL){
        AjlistNode *temp=NULL;
        for(int index=0;index<size;index++){
            cout<<"\n Adjacency list of vertex "<<index<<" :";
            temp=node[index].next;
            while(temp!=NULL){
                //temp->vId is graph node vertices
                //in this case temp->vId is same as 
                //node[temp->vId].data
                
                cout<<" "<<node[temp->vId].data;
                temp=temp->next;
            }
        }
    }else{
        cout<<"Empty Graph"<<endl;
    }
}
void Graph::dfs(int point){

    if(visit[point]==1){
        return;
    }else{
        visit[point]=1;
        cout<<" "<<point;
        AjlistNode *temp=node[point].next;
        while(temp!=NULL){
           dfs(temp->vId); 
           temp=temp->next;
        }
    }
}
int main(){
    //Create Object
    Graph g(6);
    //First set node keys
    g.setData(); 

    //Connected two node with Edges
    g.addEdge(0,1);
    g.addEdge(0,5);
    g.addEdge(1,1);
    g.addEdge(2,1);
    g.addEdge(3,0);
    g.addEdge(3,3);
    g.addEdge(4,2);
    g.addEdge(4,3);
    g.addEdge(5,1);
    g.printGraph();
    cout<<"\n DFS of node 4 : ";
    g.dfs(4); //start node 4
    return 0;
}

Output

 Adjacency list of vertex 0 : 1 5
 Adjacency list of vertex 1 : 1
 Adjacency list of vertex 2 : 1
 Adjacency list of vertex 3 : 0 3
 Adjacency list of vertex 4 : 2 3
 Adjacency list of vertex 5 : 1
 DDFS of node 4 :  4 2 1 3 0 5
//Java DFS of directed graph
public class MyGraph{

    static class AjlistNode{
        int id;//Vertices node key
        AjlistNode next;
    }
    static class Vertices{
        int data;
        AjlistNode next;
    }

    //number of Vertices
    static int size;
    public int visit[];
    public Vertices node[];

    MyGraph(int size){
        //set value
        this.size=size;
        node=new Vertices[size];
        visit=new int[size];
    }

    //set initial node value
    public void setData(){
        if(node==null){
            System.out.println("\nEmpty Graph");
        }else{
            for(int index=0;index<size;index++){
                // avoid java.lang.NullPointerException
                node[index]=new Vertices(); 
                node[index].data=index;//set your data
                node[index].next=null;
            }
        }
    }

    public void addEdge(int S,int E){
        if(S<size &&E<size &&node!=null){
            AjlistNode newEdge=new AjlistNode();
            newEdge.id=E;//end node
            newEdge.next=null;
            if(node[S].next==null){
                node[S].next=newEdge;
            }else{
                 AjlistNode temp=node[S].next;
                 while(temp.next!=null){
                    temp=temp.next;
                 }
                 temp.next=newEdge;
            }
            

           
        }else{
            System.out.println("\nEmpty Graph");
        }
    }
    public void dfs(int point){

        if(visit[point]==1){
            return;
        }else{
            visit[point]=1;
            System.out.print("  "+point);
          
            AjlistNode temp=node[point].next;
            while(temp!=null){
               dfs(temp.id); 
               temp=temp.next;
            }
        }
    }

    public void printGraph(){

        if(size>0&&node!=null){
            for(int index=0;index<size;index++){
                System.out.print("\nAdjacency list of vertex "+index+" :");
                AjlistNode temp=node[index].next;
                while(temp!=null){
                    System.out.print(" "+node[temp.id].data);
                    temp=temp.next;
                }
            }
        }
    }
    
    public static void main(String[] args) {
        int totalNode=6;
        
        MyGraph g=new MyGraph(totalNode);
        g.setData();
        //Connected two node with Edges
        g.addEdge(0,1);
        g.addEdge(0,5);
        g.addEdge(1,1);
        g.addEdge(2,1);
        g.addEdge(3,0);
        g.addEdge(3,3);
        g.addEdge(4,2);
        g.addEdge(4,3);
        g.addEdge(5,1);

        g.printGraph();
        System.out.print("\nDFS : ");
        g.dfs(4);

    }
}

Output

Adjacency list of vertex 0 : 1 5
Adjacency list of vertex 1 : 1
Adjacency list of vertex 2 : 1
Adjacency list of vertex 3 : 0 3
Adjacency list of vertex 4 : 2 3
Adjacency list of vertex 5 : 1
DFS :   4  2  1  3  0  5
#Python DFS In Directed Graph
class AjLinkeNode:
  def __init__(self,data):
    self.id=data
    self.next=None

class Vertices:
  def __init__(self,data):
    self.data=data
    self.next=None

class Graph:
  """Constructor for Graph"""
  def __init__(self, size):
    self.size=size
    self.node=[]
    self.visit=[0]*size


  def setData(self):
    if(self.size>0 and self.node!=None):
      index=0
      while(index<self.size):
        self.node.append(Vertices(index))
        index+=1

  def addEdge(self,S,E):
    #S and E is two nodes
    if(self.size>S and self.size>E):
      new_edge=AjLinkeNode(E)
      if(self.node[S].next==None):
        self.node[S].next=new_edge
      else:
        temp=self.node[S].next
        while(temp.next!=None):
          temp=temp.next
        temp.next=new_edge
    else:
      print("Invalid nodes")

  def printGraph(self):
    if(self.size>0 and self.node!=None):
      index=0
      while(index<self.size):
        print("\nAdjacency list of vertex {0} :".format(index),end=" ")
        temp=self.node[index].next
        while temp!=None:
          print("  {0}".format(temp.id),end=" ")
          temp=temp.next
        index+=1

  def dfs(self, point):
    if(self.visit[point]==1):
        return
    else:
      self.visit[point]=1
      print(point,end=" ")
      
      temp=self.node[point].next
      while(temp!=None):
        self.dfs(temp.id) 
        temp=temp.next
    
def main():
  g=Graph(6)
  g.setData() 
  #Connected two node with Edges
  g.addEdge(0,1)
  g.addEdge(0,5)
  g.addEdge(1,1)
  g.addEdge(2,1)
  g.addEdge(3,0)
  g.addEdge(3,3)
  g.addEdge(4,2)
  g.addEdge(4,3)
  g.addEdge(5,1)
  g.printGraph()
  print("\nDFS :",end=" ")
 
  g.dfs(4)

if __name__=="__main__":
    main()

Output

Adjacency list of vertex 0 :   1   5 
Adjacency list of vertex 1 :   1 
Adjacency list of vertex 2 :   1 
Adjacency list of vertex 3 :   0   3 
Adjacency list of vertex 4 :   2   3 
Adjacency list of vertex 5 :   1 
DFS : 4 2 1 3 0 5 
//C# DFS In Directed Graph
using System;
class AjlistNode{
    public int key;
    public AjlistNode next;
    public AjlistNode(int key){
        this.key=key;
        this.next=null;
    }
}
class Node{
    public int data;
    public AjlistNode next;
    public Node(int data){
        this.data=data;
        this.next=null;

    }
}
class MyGraph{
    //empty array
    public Node[]node= new Node[] {};
    public int size;
    public int[]visit= new int[] {};
    public MyGraph(int size){
        this.size=size;
        node=new Node[size];
        visit=new int[size];
    }
    public void setData(){
        if(size>0 && this.node!=null){
            for(int index=0;index<size;index++){
                node[index]=new Node(index);
            }

        }
    }
    public void addEdge(int start,int end){
        if(this.size>start && this.size>end){
            AjlistNode newEdge=new AjlistNode(end);

            if(node[start].next==null){
                node[start].next=newEdge;
            }else{
                AjlistNode temp=node[start].next;
                while(temp.next!=null){
                    temp=temp.next;
                }
                temp.next=newEdge;
            }

        }
    }
    public void printGraph(){
        if(size>0 && node.Length>0 && node!=null){
            for(int index=0;index<size;index++){
                Console.Write("\nAdjacency list of vertex {0} :",index);
                AjlistNode temp=node[index].next;
                while(temp!=null){
                    Console.Write(" "+node[temp.key].data);
                    temp=temp.next;
                }
            }
        }
    }
    public void dfs(int point){

        if(visit[point]==1){
            return;
        }else{
            visit[point]=1;
            Console.Write(" {0}",point);

            AjlistNode temp=node[point].next;
            while(temp!=null){
                dfs(temp.key); 
                temp=temp.next;
            }
        }
    }

}
class Program{

    static void Main(string[] args){
        //create object
        MyGraph g=new MyGraph(6);
        g.setData();
        //Connected two node with Edges
        g.addEdge(0,1);
        g.addEdge(0,5);
        g.addEdge(1,1);
        g.addEdge(2,1);
        g.addEdge(3,0);
        g.addEdge(3,3);
        g.addEdge(4,2);
        g.addEdge(4,3);
        g.addEdge(5,1);

        g.printGraph();
        Console.Write("\nDFS : ");
        g.dfs(4);
    }
}

Output

Adjacency list of vertex 0 : 1 5
Adjacency list of vertex 1 : 1
Adjacency list of vertex 2 : 1
Adjacency list of vertex 3 : 0 3
Adjacency list of vertex 4 : 2 3
Adjacency list of vertex 5 : 1
DFS :  4 2 1 3 0 5
<?php 
/*
* PHP Program DFS in Directed Graph
*/

class AjlistNode{
  public $key;
  public $next;
  function __construct($key){
    $this->key=$key;
    $this->next=NULL;
  }
}
class Node{
  public $data;
  public $next;
  function __construct($data){
    $this->data=$data;
    $this->next=NULL;

  }
}
class MyGraph{
 
  public $node;
  public $size;
  public $visit;
  function __construct($size){
    $this->size=$size;
    $this->node=[];  //empty array

    $this->visit=array_fill(0, $size, 0);
  }
  public function setData(){
    if($this->size>0){
      for($index=0;$index<$this->size;$index++){
        $this->node[$index]=new Node($index);
      }
      
    }
  }
  public function addEdge($start,$end){
    if($this->size > $start && $this->size>$end){
      $newEdge=new AjlistNode($end);
      if($this->node[$start]->next==NULL){
        $this->node[$start]->next=$newEdge;
      }else{

        $temp=$this->node[$start]->next;
        while($temp->next!=NULL){
         $temp=$temp->next;
        }
        $temp->next= $newEdge;
      }
    }
  }
  public function printGraph(){
    if($this->size>0 && count($this->node)>0 && $this->node!=NULL){
      for($index=0;$index<$this->size;$index++){
       echo ("<br>Adjacency list of vertex ".$index." : ");
        $temp=$this->node[$index]->next;
        while($temp!=NULL){
         echo (" ".$this->node[$temp->key]->data);
          $temp=$temp->next;
        }
      }
    }
  }
  public function dfs($point){

        if($this->visit[$point]==1){
            return;
        }else{
            $this->visit[$point]=1;
           echo ("  ".$point);
          
           $temp=$this->node[$point]->next;
            while($temp!=NULL){
               $this->dfs($temp->key); 
               $temp=$temp->next;
            }
        }
    }


}


function main(){
  //create object
  $g=new MyGraph(6);
  $g->setData();
  
  //Connected two node with Edges
  $g->addEdge(0,1);
  $g->addEdge(0,5);
  $g->addEdge(1,1);
  $g->addEdge(2,1);
  $g->addEdge(3,0);
  $g->addEdge(3,3);
  $g->addEdge(4,2);
  $g->addEdge(4,3);
  $g->addEdge(5,1);
  $g->printGraph();
  echo "<br>DFS : ";
  $g->dfs(4);
 
}
main();
?>

Output

Adjacency list of vertex 0 : 1 5
Adjacency list of vertex 1 : 1
Adjacency list of vertex 2 : 1
Adjacency list of vertex 3 : 0 3
Adjacency list of vertex 4 : 2 3
Adjacency list of vertex 5 : 1
DFS : 4 2 1 3 0 5


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