prims c 2b 2b

1#include <iostream>
2#include <vector>
3#include <queue>
4#include <functional>
5#include <utility>
6
7using namespace std;
8const int MAX = 1e4 + 5;
9typedef pair<long long, int> PII;
10bool marked[MAX];
11vector <PII> adj[MAX];
12
13long long prim(int x)
14{
15    priority_queue<PII, vector<PII>, greater<PII> > Q;
16    int y;
17    long long minimumCost = 0;
18    PII p;
19    Q.push(make_pair(0, x));
20    while(!Q.empty())
21    {
22        // Select the edge with minimum weight
23        p = Q.top();
24        Q.pop();
25        x = p.second;
26        // Checking for cycle
27        if(marked[x] == true)
28            continue;
29        minimumCost += p.first;
30        marked[x] = true;
31        for(int i = 0;i < adj[x].size();++i)
32        {
33            y = adj[x][i].second;
34            if(marked[y] == false)
35                Q.push(adj[x][i]);
36        }
37    }
38    return minimumCost;
39}
40
41int main()
42{
43    int nodes, edges, x, y;
44    long long weight, minimumCost;
45    cin >> nodes >> edges;
46    for(int i = 0;i < edges;++i)
47    {
48        cin >> x >> y >> weight;
49        adj[x].push_back(make_pair(weight, y));
50        adj[y].push_back(make_pair(weight, x));
51    }
52    // Selecting 1 as the starting node
53    minimumCost = prim(1);
54    cout << minimumCost << endl;
55    return 0;
56}