Dijkstra_algorithm_Using_Set_Data_Structure.cpp

//{ Driver Code Starts
#include <bits/stdc++.h>
using namespace std;

// } Driver Code Ends
class Solution
{
public:
    // Function to find the shortest distance of all the vertices
    // from the source vertex S.
    vector<int> dijkstra(int V, vector<vector<int>> adj[], int S)
    {
        vector<int> dist(V, 1e9);
        set<pair<int, int>> st;
        st.insert({S, 0});
        dist[S] = 0;

        while (!st.empty())
        {
            auto it = *(st.begin());
            int node = it.first;
            int distance = it.second;

            st.erase(it);

            for (auto it : adj[node])
            {
                int adjNode = it[0];
                int EdgeWeight = it[1];

                if (distance + EdgeWeight < dist[adjNode])
                {
                    if (dist[adjNode] != 1e9)
                        st.erase({dist[adjNode], adjNode});

                    dist[adjNode] = EdgeWeight + distance;
                    st.insert({adjNode, dist[adjNode]});
                }
            }
        }
        return dist;
    }
};

//{ Driver Code Starts.

int main()
{
    int t;
    cin >> t;
    while (t--)
    {
        int V, E;
        cin >> V >> E;
        vector<vector<int>> adj[V];
        int i = 0;
        while (i++ < E)
        {
            int u, v, w;
            cin >> u >> v >> w;
            vector<int> t1, t2;
            t1.push_back(v);
            t1.push_back(w);
            adj[u].push_back(t1);
            t2.push_back(u);
            t2.push_back(w);
            adj[v].push_back(t2);
        }
        int S;
        cin >> S;

        Solution obj;
        vector<int> res = obj.dijkstra(V, adj, S);

        for (int i = 0; i < V; i++)
            cout << res[i] << " ";
        cout << endl;
    }

    return 0;
}

// } Driver Code Ends