单源最短路径

#include <climits>
#include <cstdio>
#include <iostream>
#include <queue>
#include <vector>

using namespace std;

void dfs(const vector<long long>& path, long long i)
{
    if (i == 1) {
        printf("1");
        return;
    }
    dfs(path, path[i]);
    printf(" %lld", i);
}

int main()
{
    long long n, m;
    cin >> n >> m;

    vector<vector<pair<long long, long long>>> graph(n + 1);
    for (long long i = 0; i < m; i++) {
        long long u, v, w;
        cin >> u >> v >> w;
        graph[u].emplace_back(v, w);
        graph[v].emplace_back(u, w);
    }

    vector<long long> dist(n + 1, LLONG_MAX);
    vector<long long> path(n + 1, 0);
    vector<bool> collected(n + 1, false);

    priority_queue<pair<long long, long long>, vector<pair<long long, long long>>, greater<>> pq;
    dist[1] = 0;
    pq.emplace(0, 1);

    while (!pq.empty()) {
        auto [d, u] = pq.top();
        pq.pop();
        if (collected[u])
            continue;
        collected[u] = true;
        for (auto [v, w] : graph[u]) {
            if (dist[u] + w < dist[v]) {
                dist[v] = dist[u] + w;
                path[v] = u;
                pq.emplace(dist[v], v);
            }
        }
    }

    if (dist[n] == LLONG_MAX) {
        printf("-1");
        return 0;
    }

    dfs(path, n);
    return 0;
}