Graph implementation using STL for competitive programming | Set 2 (Weighted graph)

In Set 1, unweighted graph is discussed. In this post, weighted graph representation using STL is discussed. The implementation is for adjacency list representation of weighted graph. 

We use two STL containers to represent graph: 

The idea is to use a vector of pair vectors. Below code implements the same.




// C++ program to represent undirected and weighted graph
// using STL. The program basically prints adjacency list
// representation of graph
#include <bits/stdc++.h>
using namespace std;
 
// To add an edge
void addEdge(vector <pair<int, int> > adj[], int u,
                                     int v, int wt)
{
    adj[u].push_back(make_pair(v, wt));
    adj[v].push_back(make_pair(u, wt));
}
 
// Print adjacency list representaion ot graph
void printGraph(vector<pair<int,int> > adj[], int V)
{
    int v, w;
    for (int u = 0; u < V; u++)
    {
        cout << "Node " << u << " makes an edge with \n";
        for (auto it = adj[u].begin(); it!=adj[u].end(); it++)
        {
            v = it->first;
            w = it->second;
            cout << "\tNode " << v << " with edge weight ="
                 << w << "\n";
        }
        cout << "\n";
    }
}
 
// Driver code
int main()
{
    int V = 5;
    vector<pair<int, int> > adj[V];
    addEdge(adj, 0, 1, 10);
    addEdge(adj, 0, 4, 20);
    addEdge(adj, 1, 2, 30);
    addEdge(adj, 1, 3, 40);
    addEdge(adj, 1, 4, 50);
    addEdge(adj, 2, 3, 60);
    addEdge(adj, 3, 4, 70);
    printGraph(adj, V);
    return 0;
}




# Python3 program to represent undirected
# and weighted graph. The program basically
# prints adjacency list representation of graph
 
# To add an edge
def addEdge(adj, u, v, wt):
     
    adj[u].append([v, wt])
    adj[v].append([u, wt])
    return adj
 
# Print adjacency list representaion ot graph
def printGraph(adj, V):
     
    v, w = 0, 0
    for u in range(V):
        print("Node", u, "makes an edge with")
 
        for it in adj[u]:
            v = it[0]
            w = it[1]
            print("\tNode", v, "with edge weight =", w)
             
        print()
 
# Driver code
if __name__ == '__main__':
     
    V = 5
    adj = [[] for i in range(V)]
 
    adj = addEdge(adj, 0, 1, 10)
    adj = addEdge(adj, 0, 4, 20)
    adj = addEdge(adj, 1, 2, 30)
    adj = addEdge(adj, 1, 3, 40)
    adj = addEdge(adj, 1, 4, 50)
    adj = addEdge(adj, 2, 3, 60)
    adj = addEdge(adj, 3, 4, 70)
 
    printGraph(adj, V)
 
# This code is contributed by mohit kumar 29

Output: 

Node 0 makes an edge with 
    Node 1 with edge weight =10
    Node 4 with edge weight =20

Node 1 makes an edge with 
    Node 0 with edge weight =10
    Node 2 with edge weight =30
    Node 3 with edge weight =40
    Node 4 with edge weight =50

Node 2 makes an edge with 
    Node 1 with edge weight =30
    Node 3 with edge weight =60

Node 3 makes an edge with 
    Node 1 with edge weight =40
    Node 2 with edge weight =60
    Node 4 with edge weight =70

Node 4 makes an edge with 
    Node 0 with edge weight =20
    Node 1 with edge weight =50
    Node 3 with edge weight =70

This article is contributed by Sahil Chhabra (akku). If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
 




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