Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- #include <iostream>
- #include <vector>
- #include <queue>
- using namespace std;
- const int maxn = 1e5 + 10;
- const int INF = 2e9;
- vector<pair<int, int>> graph[maxn];
- int n, m;
- struct node {
- int idx, cost;
- node () {}
- node(int _idx, int _cost) {
- idx = _idx;
- cost = _cost;
- }
- bool operator < (const node &tmp) const {
- return cost > tmp.cost;
- }
- };
- void prim() {
- vector<int> distance(n, INF);
- vector<bool> visited(n, false);
- distance[0] = 0;
- priority_queue<node> pq;
- pq.push(node(0, 0));
- int mst = 0;
- while(!pq.empty()) {
- node c = pq.top();
- pq.pop();
- if(visited[c.idx]) {
- continue;
- }
- visited[c.idx] = true;
- mst += c.cost;
- for(int i = 0; i < (int) graph[c.idx].size(); i++) {
- int neighbour = graph[c.idx][i].first;
- int weight = graph[c.idx][i].second;
- if(!visited[neighbour] and weight < distance[neighbour]) {
- pq.push(node(neighbour, weight));
- distance[neighbour] = weight;
- }
- }
- }
- cout << mst << endl;
- }
- int main() {
- cin >> n >> m;
- for(int i = 0; i < m; i++) {
- int a, b, c;
- cin >> a >> b >> c;
- a--; b--;
- graph[a].push_back(make_pair(b, c));
- graph[b].push_back(make_pair(a, c));
- }
- prim();
- return 0;
- }
- /*
- 6 9
- 5 4 9
- 5 1 4
- 1 4 1
- 1 2 2
- 2 4 3
- 2 3 3
- 2 6 7
- 3 6 8
- 4 3 5
- **/
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement