Cod sursa(job #3224784)

Utilizator AndreiBOTOBotocan Andrei AndreiBOTO Data 16 aprilie 2024 10:53:23
Problema Santa Scor 100
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 3.6 kb
#include <bits/stdc++.h>

#pragma optimize GCC ("Ofast")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

///#include <tryhardmode>
///#include <GODMODE::ON>

using namespace std;

ifstream fin ("santa.in");
ofstream fout ("santa.out");

#define cin fin
#define cout fout

const int NMAX=45e3+5;

set<int>cbc[NMAX];
vector<int>v[NMAX];

stack<int>stiva;
vector<int>art;
vector<int>way;

bool path[NMAX];
bool viz[NMAX];
int ti[NMAX];
int tmin[NMAX];
int total;
int kon;
int n;

void dfs(int p,int tata)
{
    int fii=0;
    ti[p]=++kon;
    tmin[p]=kon;
    stiva.push(p);
    for(auto i:v[p])
    {
        if(i!=tata)
        {
            if(!ti[i])
            {
                dfs(i,p);
                tmin[p]=min(tmin[p],tmin[i]);
                path[p]|=path[i];
                if(tmin[i]>=ti[p])
                {
                    if(!path[i])
                    {
                        while(stiva.top()!=i)
                            stiva.pop();
                        stiva.pop();
                        continue;
                    }
                    total++;
                    while(stiva.top()!=i)
                    {
                        cbc[total].insert(stiva.top());
                        stiva.pop();
                    }
                    cbc[total].insert(stiva.top());
                    stiva.pop();
                    cbc[total].insert(p);
                    art.push_back(p);
                }
            }
            else
                tmin[p]=min(tmin[p],ti[i]);
        }
    }
}

bool backt(int step,int saiz,int p,int to)
{
    for(auto i:v[p])
    {
        if(!viz[i])
        {
            viz[i]=true;
            way.push_back(i);
            if(step==saiz-1)
            {
                if(i==to)
                    return true;
                if(to==-1)
                    return true;
                return false;
            }
            else
            {
                if(i!=to)
                {
                    if(backt(step+1,saiz,i,to)==true)
                        return true;
                }
                way.pop_back();
                viz[i]=false;
            }
        }
    }
    return false;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int m,i,j,s,e,q;
    cin>>n>>m;
    for(i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    cin>>s>>e>>q;
    art.push_back(s);
    path[e]=true;
    dfs(s,0);
    if(!path[s])
    {
        cout<<"No chance";
        return 0;
    }
    if(cbc[1].find(q)==cbc[1].end())
    {
        reverse(cbc+1,cbc+total+1);
        reverse(art.begin(),art.end());
        if(cbc[1].find(q)==cbc[1].end())
        {
            cout<<"No chance";
            return 0;
        }
    }
    art[0]=q;
    way.push_back(q);
    for(i=1;i<=n;i++)
        viz[i]=true;
    for(i=1;i<=total;i++)
    {
        for(auto it:cbc[i])
            viz[it]=false;
        viz[art[i-1]]=true;
        if(i==total)
        {
            if(backt(1,cbc[i].size(),art[i-1],-1)==false)
            {
                cout<<"No chance";
                return 0;
            }
        }
        else
        {
            if(backt(1,cbc[i].size(),art[i-1],art[i])==false)
            {
                cout<<"No chance";
                return 0;
            }
        }
    }
    cout<<way.size()<<"\n";
    for(auto i:way)
        cout<<i<<" ";
    return 0;
}