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  1.          #include<cstdio>
  2.          #include<list>
  3.          #include<queue>
  4.  
  5.         using namespace std;
  6.  
  7.      int V;
  8.      list<int>* point;
  9.  
  10.  
  11.  
  12.       void Graph_Make(int V)
  13.       {
  14.           point=new list<int>[V];
  15.       }
  16.  
  17.  
  18.       void Edge_Create(int u,int v)
  19.       {
  20.          point[u].push_back(v);
  21.       }
  22.  
  23.      void Show_Graph()
  24.      {
  25.         int i;
  26.         for(i=0;i<V;i++)
  27.         {
  28.           printf("\n");
  29.           printf("%d :",i);
  30.           for(auto it=point[i].begin();it!=point[i].end();it++)
  31.                printf("%d ",*it);
  32.         }
  33.      }
  34.  
  35.    bool Check_for_cycle(int v,bool array1[],bool stack1[])
  36.    {
  37.       array1[v]=true;
  38.       stack1[v]=true;
  39.  
  40.       for(auto it=point[v].begin();it!=point[v].end();it++)
  41.       {
  42.           if(!array1[*it]&&Check_for_cycle(*it,array1,stack1))
  43.              return(true);
  44.           else if(stack1[*it])
  45.              return(true);
  46.       }
  47.       stack1[v]=false;
  48.       return(false);
  49.    }
  50.  
  51.  
  52.     bool is_Cycle()
  53.     {
  54.        bool array1[V],stack1[V];
  55.        int i;
  56.        for(i=0;i<V;i++)
  57.        {
  58.             array1[i]=false;
  59.             stack1[i]=false;
  60.        }
  61.        for(i=0;i<V;i++)
  62.        {
  63.           if(array1[i]==false)
  64.          {
  65.            if(Check_for_cycle(i,array1,stack1))
  66.              return true;
  67.          }
  68.        }
  69.       return false;
  70.     }
  71.  
  72.  
  73.  
  74.       int main(void)
  75.       {
  76.          int s;
  77.          bool check;
  78.          printf("\n Enter the vertices in a graph");
  79.          scanf("%d",&V);
  80.          Graph_Make(V);
  81.          Edge_Create(1,0);
  82.          Edge_Create(0,2);
  83.          Edge_Create(3,1);
  84.          Edge_Create(2,3);
  85.          Show_Graph();
  86.          check=is_Cycle();
  87.          if(check==true)
  88.             printf("\n Graph has a cycle");
  89.          else
  90.             printf("\n Graph doesn't have any cycle");
  91.          return(0);
  92.          }
  93.  
Success #stdin #stdout 0s 3476KB
comments (?)
stdin
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4
stdout
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 Enter the vertices in a graph
0 :2 
1 :0 
2 :3 
3 :1 
 Graph has a cycle
https://ideone.com/TtFsJA
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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