```// Program to find Dijkstra's shortest path using
// priority_queue in STL
#include<bits/stdc++.h>
using namespace std;
# define INF 0x3f3f3f3f

// iPair ==> Integer Pair
typedef pair<int, int> iPair;

// This class represents a directed graph using
// adjacency list representation
class Graph
{
int V; // No. of vertices

// In a weighted graph, we need to store vertex
// and weight pair for every edge
list< pair<int, int> > *adj;

public:
Graph(int V); // Constructor

// function to add an edge to graph
void addEdge(int u, int v, int w);

// prints shortest path from s
void shortestPath(int s);
};

// Allocates memory for adjacency list
Graph::Graph(int V)
{
this->V = V;
adj = new list<iPair> [V];
}

void Graph::addEdge(int u, int v, int w)
{
}

// Prints shortest paths from src to all other vertices
void Graph::shortestPath(int src)
{
// Create a priority queue to store vertices that
// are being preprocessed. This is weird syntax in C++.
// Refer below link for details of this syntax
// https://www.geeksforgeeks.org/implement-min-heap-using-stl/
priority_queue< iPair, vector <iPair> , greater<iPair> > pq;

// Create a vector for distances and initialize all
// distances as infinite (INF)
vector<int> dist(V, INF);

// Insert source itself in priority queue and initialize
// its distance as 0.
pq.push(make_pair(0, src));
dist[src] = 0;

vector<bool> f(V, false);

/* Looping till priority queue becomes empty (or all
distances are not finalized) */
while (!pq.empty())
{
// The first vertex in pair is the minimum distance
// vertex, extract it from priority queue.
// vertex label is stored in second of pair (it
// has to be done this way to keep the vertices
// sorted distance (distance must be first item
// in pair)
int u = pq.top().second;
pq.pop();
f[u] = true;

// 'i' is used to get all adjacent vertices of a vertex
list< pair<int, int> >::iterator i;
for (i = adj[u].begin(); i != adj[u].end(); ++i)
{
// Get vertex label and weight of current adjacent
// of u.
int v = (*i).first;
int weight = (*i).second;

// If there is shorted path to v through u.
if (f[v] == false && dist[v] > dist[u] + weight)
{
// Updating distance of v
dist[v] = dist[u] + weight;
pq.push(make_pair(dist[v], v));
}
}
}

// Print shortest distances stored in dist[]
printf("Vertex Distance from Source\n");
for (int i = 0; i < V; ++i)
printf("%d \t\t %d\n", i, dist[i]);
}

// Driver program to test methods of graph class
int main()
{
// create the graph given in above fugure
int V = 9;
Graph g(V);

// making above shown graph

g.shortestPath(0);

return 0;
}
```

### Output:

```Vertex Distance from Source
0 		 0
1 		 4
2 		 12
3 		 19
4 		 21
5 		 11
6 		 9
7 		 8
8 		 14
```