graph.cpp

#include<bits/stdc++.h>
using namespace std;

class graph{
    public:
        unordered_map<int, list<int> > adj;

        void addEdge(int u,int v,bool direction){
            //direction = 0 -> undirected graph
            //direction = 1 -> directed graph

            //create an edge from u to v
            adj[u].push_back(v);

            if(direction==0){
                adj[v].push_back(u);
            }
        }

        void printAdjList(){
            for(auto i:adj){
                cout<<i.first<<"->";
                for(auto j: i.second){
                    cout<<j<<" ";
                }
                cout<<endl;
            }
        }

};

int main(){
    int n;
    cout<<"Enter the number of nodes"<<endl;
    cin>>n;
    int m;
    cout<<"Enter the number of edges"<<endl;
    cin>>m;

    graph g;

    for(int i=0;i<m;i++){
        int u,v;
        cin>>u>>v;
        // creating an undirected graph
        g.addEdge(u,v,0);
    }
    //printing graph
    g.printAdjList();
    return 0;
}