From d3b3ad2741b6e8962b397dbdbbe2631c2c11312c Mon Sep 17 00:00:00 2001
From: Rohit Singh <62849015+Rohit-Singh-Ch@users.noreply.github.com>
Date: Thu, 1 Oct 2020 22:16:20 +0530
Subject: [PATCH] Create detect Cycle in Graph by BFS

---
 detect Cycle in Graph by BFS | 130 +++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 detect Cycle in Graph by BFS

diff --git a/detect Cycle in Graph by BFS b/detect Cycle in Graph by BFS
new file mode 100644
index 00000000..36631f2b
--- /dev/null
+++ b/detect Cycle in Graph by BFS	
@@ -0,0 +1,130 @@
+-1--->if any vertex unvisited 
+                 0---->if any vertex visited and push into the stack
+                 1---->if any vertex poped(means already complete don't considered) 
+
+                 if any vertex alreay adjacency visited and not poped means in 0 position then graph conation cycle
+
+
+
+                 #include<stdio.h>
+		 #include<stdlib.h>
+		 #define v 5
+		 int arr[v][v];
+		 int visited[v];
+		 int stack[v];
+		 int top=-1;
+
+                 void push(int data)
+                 {
+                   stack[++top]=data;
+                 }
+
+                 int pop()
+                 {
+                   return stack[top--];
+                 }
+
+                 int peek()
+                 {
+	           return stack[top];
+                 }
+
+                 void Dfs()
+                 {
+	           int i,x,y,flag=0;
+	           while(top!=-1)
+	          {
+		     for(i=0;i<v;i++)
+		     {
+		       x=peek();
+		       if(arr[x][i]==1) 
+		       {
+		  	  if(visited[i]==-1)
+			  {
+		  	     push(i);
+		  	     visited[i]=0;
+		  	     i=-1;
+			  }
+			  else
+			  {
+			     if(visited[i]==0)
+			     {
+				flag=1;
+				break;
+			     }
+			  }
+		        }
+	             }
+	             if(flag==1)
+		     {
+	                printf("\nGraph conation cycle : %d---%d",x,i);
+	                break;
+	             }
+	             else
+		     {
+			y=pop();
+			visited[y]=1;
+			  
+		     } 
+	           }
+	          if(flag!=1)
+	          printf("Graph contain no cycle ");
+	       }
+
+	          or
+		  ===
+           
+	      void Dfs()
+              {
+	         int i,x,y,flag=0;
+	         for(i=0;i<v;i++)
+	         {
+		    x=peek();
+		    if(arr[x][i]==1) 
+	            {
+		        if(visited[i]==-1)
+			{
+		  	   push(i);
+		  	   visited[i]=0;
+		  	   i=-1;
+			}
+			else
+			{
+			    if(visited[i]==0)
+			    {
+				flag=1;
+				break;
+			     }
+			}
+		    }
+	         }
+	         if(flag==1)
+	           printf("\nGraph conation cycle");
+	         else
+	         {
+		   y=pop();
+		   visited[y]=1;
+		   if(top!=-1)
+		      Dfs();
+		   else
+		     printf("\nGraph conation no cycle ") ; 
+	         }   
+
+               } 
+
+
+               void main()
+               {
+	          int i,j,root;
+	          printf("enter adjacency matrix : \n");
+	          for(i=0;i<v;i++)
+	            for(j=0;j<v;j++)
+	              scanf("%d",&arr[i][j]);
+	          for(i=0;i<v;i++)
+	             visited[i]=-1;
+	          printf("from Where you want to start: ");
+	          scanf("%d",&root);
+	          visited[root]=0;
+	          push(root);
+	          Dfs();     
+               }