LightOJ - Country Roads

#include <bits/stdc++.h>
using namespace std;

const int maxN = 510;
vector<pair<int,int>> adj[maxN];
int dist[maxN];

void dijkstra (int source,int n) {
    for (int i = 0; i < n; ++i) dist[i] = (int) 1e7;
    dist[source] = 0;
    priority_queue<pair<int,int>> pq;
    pq.push(make_pair(0,source));
    while (!pq.empty()) {
        int node = pq.top().second;
        int node_cost = abs(pq.top().first);
        pq.pop();
        if (dist[node] < node_cost) continue;
        for (pair<int,int> child : adj[node]) {
            if (dist[child.first] > max(child.second,node_cost)) {
                dist[child.first] = max(child.second,node_cost);
                pq.push(make_pair(-dist[child.first],child.first));
            }
        }
    }
}

int main () {
     ios::sync_with_stdio(false);
     cin.tie(nullptr);
     cout.tie(nullptr);
     int T;
     cin >> T;
     for (int test_case = 1; test_case <= T; ++test_case) {
         int n,m;
         cin >> n >> m;
         for (int i = 0; i < n; ++i) adj[i].clear();
         for (int i = 1; i <= m; ++i) {
             int u,v,c;
             cin >> u >> v >> c;
             adj[u].push_back(make_pair(v,c));
             adj[v].push_back(make_pair(u,c));
         }
         int source;
         cin >> source;
         dijkstra (source,n);
         //for (int i = 0; i < n; ++i) cout << max_cost[i] << ' ';
         cout << "Case " << test_case << ":\n";
         for (int i = 0; i < n; ++i) cout << (dist[i] == (int) 1e7 ? "Impossible" : to_string(dist[i])) << '\n';
     }
     //cerr << "Time elapsed :" << clock() * 1000.0 / CLOCKS_PER_SEC << " ms" << '\n';
}