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P43859
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| #include <iostream> | |
| #include <vector> | |
| #include <queue> | |
| #include <utility> | |
| #include <map> | |
| using namespace std; | |
| const int infinit = 999999999; | |
| using Arc = pair<int, int>; // cost, destí | |
| using Graph = vector<vector<Arc>>; // llistes d'adjacència | |
| int dijkstra(const Graph& G, int x, int y) { | |
| int n = G.size(); | |
| vector<int> d(n, infinit); | |
| d[x] = 0; | |
| priority_queue<Arc, vector<Arc>, greater<Arc>> pq; | |
| pq.push({0, x}); | |
| while (not pq.empty()) { | |
| int l = pq.top().first; | |
| int u = pq.top().second; | |
| pq.pop(); | |
| if (d[u] >= l) { | |
| for (Arc a : G[u]) { | |
| int c = a.first; | |
| int v = a.second; | |
| if (d[v] > d[u] + c) { | |
| d[v] = d[u] + c; | |
| pq.push({d[v], v}); | |
| } } } } | |
| return d[y]; | |
| } | |
| int main() { | |
| int n, m; | |
| while (cin >> n >> m) { | |
| Graph G(n); | |
| for (int i = 0; i < m; ++i) { | |
| int u, v, c; | |
| cin >> u >> v >> c; | |
| G[u].push_back({c, v}); | |
| } | |
| int x, y; | |
| cin >> x >> y; | |
| int d = dijkstra(G, x, y); | |
| if (d == infinit) cout << "no path from " << x << " to " << y << endl; | |
| else cout << d << endl; | |
| } | |
| } |
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