adjacency_list.cpp

#include <iostream>
#include<unordered_map>
#include<list>
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 node:"<<endl;
    cin>>n;

    int m;
    cout<<"Enter the number of edge"<<endl;
    cin>>m;

    graph g;
    for(int i = 0; i<m; i++){
        int u,v;
        cout<<"Enter source node:";
        cin>>u;
        cout<<"Enter destination node:";
        cin>>v;
        g.addEdge(u,v,0);
    }

    g.printAdjlist();
    return 0;
}