R1P1 Lant

#include <fstream>
#include <iostream>
#include <algorithm>

using namespace std ;

ifstream f("lant.in");
ofstream g("lant.out");

int a[50][50] ;
int n , m , p , q , r , gata = 0 ;
int P[50] , X[50] ;

void citire()
{
   f >> n >> m ;
   for( int i = 1 ; i <= m ; ++i )
      {
       int x , y ;
       f >> x >> y;
       a[x][y] = a[y][x] =  1 ;
      }
   f >> p >> q >> r ;
}

void afis( int k )
{
    for ( int i = 1 ; i <= k ; ++i )
       g << X[i] << " " ;
    g << "\n" ;
    gata = 1 ;
}

void back( int k )
{
    if( gata == 0 )
    {
        for( int i = 1 ; i <= n ; ++i )
            if( !P[i] && a[X[k-1]][i] == 1 && gata == 0 )
            {
                X[k] = i ;
                P[i] = 1 ;
                if( i == q )
                    {
                     int ok = 1 ;
                     for ( int j = 2 ; j < k && ok ; ++j )
                        if ( X[j] == r )
                            ok = 0 ;
                     if ( !ok )
                        afis ( k ) ;
                    }
                else
                    back ( k + 1 ) ;
                P[i] = 0 ;
            }
    }

}

int main()
{
    citire();
    //initializam cu p
    X[1] = p ;
    P[p] = 1 ;
    back ( 2 ) ;
    f.close();
    g.close();
    return 0;
}