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| 1 | +/* Submitted by |
| 2 | + Name:REDDI HAREESH |
| 3 | + Roll Number:150101051 |
| 4 | +*/ |
| 5 | +//I am starting indexes of nodes from 0 and there is always a path from a node to itself |
| 6 | +#include<iostream> |
| 7 | +#include <list> |
| 8 | +using namespace std; |
| 9 | + |
| 10 | +class Graph |
| 11 | +{ |
| 12 | + int V; |
| 13 | + list<int> *adjacent; |
| 14 | + int isReachableUtil(int visited[], int a,int b); |
| 15 | + |
| 16 | +public: |
| 17 | + Graph(int V); |
| 18 | + void addEdge(int v, int w); |
| 19 | + int isReachable(int a, int b); |
| 20 | +}; |
| 21 | + |
| 22 | +Graph::Graph(int V) |
| 23 | +{ |
| 24 | + this->V = V; |
| 25 | + adjacent = new list<int>[V]; |
| 26 | +} |
| 27 | + |
| 28 | +void Graph::addEdge(int a, int b) |
| 29 | +{ |
| 30 | + adjacent[a].push_back(b); // Add b to a list. |
| 31 | +} |
| 32 | + |
| 33 | +int Graph::isReachableUtil(int visited[], int a,int b) |
| 34 | +{ |
| 35 | + if(a==b) |
| 36 | + { |
| 37 | + return 1; |
| 38 | + } |
| 39 | + visited[a] = 1; |
| 40 | + |
| 41 | + list<int>::iterator itr; |
| 42 | + |
| 43 | + for(itr = adjacent[a].begin(); itr != adjacent[a].end(); ++itr) |
| 44 | + { |
| 45 | + if (!visited[*itr] && isReachableUtil(visited,*itr,b)) |
| 46 | + return 1; |
| 47 | + } |
| 48 | + |
| 49 | + return 0; |
| 50 | +} |
| 51 | +int Graph::isReachable(int a, int b) |
| 52 | +{ |
| 53 | + int visited[V]; |
| 54 | + |
| 55 | + for(int i = 0; i < V; i++) |
| 56 | + { |
| 57 | + visited[i] = 0; |
| 58 | + } |
| 59 | + |
| 60 | + return isReachableUtil(visited,a,b); |
| 61 | +} |
| 62 | +int main() |
| 63 | +{ int n,e,i,j,u,v; |
| 64 | +//create a graph |
| 65 | + cout<<"Enter number of nodes of the graph:"; |
| 66 | + cin>>n; |
| 67 | + cout<<"\n"; |
| 68 | + Graph g(n); |
| 69 | + cout<<"Enter number of edges of the graph:"; |
| 70 | + cin>>e; |
| 71 | + cout<<"\n"; |
| 72 | + int matrix[n][n]; |
| 73 | + for(i=0;i<n;i++) |
| 74 | + { |
| 75 | + for(j=0;j<n;j++) |
| 76 | + { |
| 77 | + matrix[i][j]=0; |
| 78 | + } |
| 79 | + } |
| 80 | + if(e>0) |
| 81 | + { |
| 82 | + cout<<"Enter the Edges:\n"; |
| 83 | + } |
| 84 | + for(i=0;i<e;i++) |
| 85 | + { |
| 86 | + cin>>u>>v; |
| 87 | + matrix[u][v]=1; |
| 88 | + g.addEdge(u, v); |
| 89 | + } |
| 90 | + cout<<"\n"; |
| 91 | +//Matrix representation of the graph |
| 92 | + cout<<"The matrix representation of the graph is:\n"; |
| 93 | + for(i=0;i<n;i++) |
| 94 | + { |
| 95 | + for(j=0;j<n;j++) |
| 96 | + { |
| 97 | + cout<<matrix[i][j]; |
| 98 | + cout<<"\t"; |
| 99 | + } |
| 100 | + cout<<"\n"; |
| 101 | + } |
| 102 | + |
| 103 | + for(i=0;i<n;i++) |
| 104 | + { |
| 105 | + for(j=0;j<n;j++) |
| 106 | + { |
| 107 | + if(g.isReachable(i,j)) |
| 108 | + cout<< "\nThere is a path from node " << i << " to node " << j; |
| 109 | + else |
| 110 | + cout<< "\nThere is no path from node " << i << " to node " << j; |
| 111 | + } |
| 112 | + cout<<"\n"; |
| 113 | + } |
| 114 | + cout<<"\n\n"; |
| 115 | + return 0; |
| 116 | +} |
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