dijkstra by pair

#include<bits/stdc++.h>
using namespace std;
#define M 101000
#define INF 1e18+7
#define ll long long
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mp make_pair
vector<pll>adj[M];
ll dis[M];
ll parent[M];
ll start;
void dijkstra(ll source)
{
  for(ll i=0;i<M;i++)
  {
      dis[i]=INF;
      parent[i]=-1;
  }
  priority_queue<pair<ll,ll>,vector<pair<ll,ll> >,greater<pair<ll,ll> > >pq;
  dis[source]=0;
  pq.push(mp(source,0));
  while(!pq.empty())
  {
      pll p=pq.top();
      pq.pop();
     // cout<<p.first<<endl;
      if(p.second>dis[p.first])
        continue;
      for(ll i=0;i<adj[p.first].size();i++)
      {
          pii v=adj[p.first][i];
          ll city=v.first;
          ll d=v.second;
          if(dis[city]>d+dis[p.first])
          {
              dis[city]=d+dis[p.first];
              pq.push(mp(city,dis[city]));
              parent[city]=p.first;
          }
      }
  }
  return;
}
void printpath(ll v)
{
    if(v==start)
    {
        cout<<v<<" ";
        return;
    }
    printpath(parent[v]);
    cout<<v<<" ";
}
int main()
{
    ll m,n;
    cin>>n>>m;
    while(m--)
    {
        int u,v,w;
        cin>>u>>v>>w;
        adj[u].push_back(mp(v,w));
        adj[v].push_back(mp(u,w));
    }
    start=1;
    dijkstra(1);
    if(dis[n]==INF)
    {
        cout<<-1<<endl;
        return 0;
    }
    printpath(n);
    cout<<endl;
    //cout<<dis[n]<<endl;
    return 0;

}