Prim’s MST Code

typedef pair<int, int> ii;

priority_queue<ii, vector<ii>, greater<ii>> pq;

vector<bool> taken;

taken.assign(V, false);

taken[0] = true;

mst_cost = 0;

for (auto it = edge[0].begin(); it != edge[0].end; it++)
    pq.push(*it);

while (!pq.empty())
{
    ii front = pq.top(); pq.pop();

    u = front.second, w = front.first;

    if (!taken[u])
    {
        for (auto it = edge[u].begin(); it != edge[u].end(); it++)
            pq.push(*it);
    }
}