20C Codeforces - Dijkstra - Solution

20C Codeforces - Dijkstra

Solution in c++

#include <bits/stdc++.h>

using namespace std;
#define pii pair<int ,int>
priority_queue<pii > q;
int nodes,edges;
vector<pii > adj[100009];
vector<int> dist,modi,vis(100009);

void print_it(int sank)
{
    if(sank!=1)print_it(modi[sank]);
    cout<<sank<<" ";
}

int main()
{
    if(7==4)
    {
        en:
            cout<<"-1\n";
            return 0;
    }
    cin>>nodes>>edges;
    modi.resize(nodes+1);
    dist.resize(nodes+1);
    for(int i=0;i<=nodes;i++){dist[i]=INFINITY;modi[i]=-1;}

    dist[1]=0;

    for(int i=0;i<edges;i++)
    {
        int t1,t2,t3;
        cin>>t1>>t2>>t3;
        adj[t1].push_back(make_pair(t2,t3));
        adj[t2].push_back(make_pair(t1,t3));
    }
    q.push({0,1});
    while(q.size()>0)
    {
        int s=q.top().second;q.pop();
        if(vis[s])continue;
        vis[s]=1;

        for(auto u: adj[s])
        {
             int u1=u.first,u2=u.second;

            if(dist[u1]>dist[s]+u2 && !vis[u1])
            {
                dist[u1]=dist[s]+u2;

                modi[u1]=s;

                q.push({-dist[u1],u1});
            }

        }

    }
    if(modi[nodes]==-1)goto en;

    print_it(nodes);

     return 0;
}

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About Mohamed Sobhi

My name is Mo.Sobhy ,I study at School excelling high school in Ain Shams ,Cairo
My hobbies is programming ,and web development ,playing chess and writing horror stories.