CCCPaste

Dijkstra

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

const int N = 1e5;

int n, m;
vector<pair<int, int>> g[N];

pair<vector<int>, vector<int>> dijkstra(int s) {
vector<int> dis(n + 1, INT_MAX), par(n + 1, -1);
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
dis[s] = 0;
pq.push({0, s});
while (!pq.empty()) {
auto [d, u] = pq.top();
pq.pop();
if (dis[u] < d) continue;
for (auto [v, w] : g[u]) {
if (d + w < dis[v]) {
dis[v] = d + w;
pq.push({dis[v], v});
par[v] = u;
}
}
}
return {dis, par};
}

void solve()
{
cin >> n >> m;
for (int i = 1; i <= m; i++) {
int u, v, w;
cin >> u >> v >> w;
g[u].push_back({v, w});
g[v].push_back({u, w});
}
auto [dis, par] = dijkstra(1);
int q;
cin >> q;
while (q--) {
int d;
cin >> d;
cout << dis[d] << '\t';
vector<int> path;
while (d != -1) {
path.push_back(d);
d = par[d];
}
reverse(path.begin(), path.end());
for (int i = 0; i < path.size() - 1; i++) {
cout << path[i] << " -> ";
}
cout << path.back() << '\n';
}
}

int main()
{
int t = 1;
// cin >> t;
for (int i = 1; i <= t; i++)
{
solve();
}
return 0;
}