ALGR: Dijkstra:BFS_directed_weighted_shortest path

#include<cstdio>
#include<vector>
#include<queue>
#include<cstdlib>
#define INF 2147483647 // 2^31 - 1
using namespace std;

void Dijkstra_BFS_weighted_directed(vector<vector<pair<int,int>>> gr, int src)
{
    int distance[gr.size()] ;// keeps shortest distance from source to node
    fill_n(distance, gr.size(), INF);
    distance[src] = 0;
    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> q;// using priority queue will reduce complexity
    q.push(make_pair(distance[src], src));
    while(!q.empty())
    {
        int u=q.top().second;
        q.pop();
        for(int i=0; i<gr[u].size(); i++)
        {
            int v = gr[u][i].first;
            int cost_of_uv = gr[u][i].second;
            if(distance[u]+cost_of_uv < distance[v])
            {
                distance[v] = distance[u]+cost_of_uv;
                q.push(make_pair(distance[v],v));
            }
        }
    }
    // printing distance of all nodes
    printf("Distance from src=%d to...\n", src);
    for(int i=1; i< gr.size(); i++){
        printf("%d: %d\n", i, distance[i]);
    }
}

int main()
{
    int n, e;
    scanf("%d %d", &n, &e);
    vector<vector<pair<int,int>>> gr;//

    gr.clear();
    gr.resize(n+1);
    // taking input for directed-weighted graph
    for(int i=0; i<e; i++)
    {
        int u,v,w;
        scanf("%d %d %d", &u, &v, &w);
        gr[u].push_back(make_pair(v,w));
        //gr[v].push_back(make_pair(u,w));
    }
    Dijkstra_BFS_weighted_directed(gr, 4);
     //printing list
//    for(int i=1; i<gr.size(); i++){
//        printf("%d: ", i);
//        for(int j=0; j<gr[i].size(); j++){
//            printf("->%d( %d )", gr[i][j].first, gr[i][j].second);
//        }
//        printf("\n");
//    }


}