// FONCTION DE FOWARD CHECKING
        public List <List <int> > Foward_Checking(GrilleSudoku s)
        {
            List <List <int> > LesPoss = new List <List <int> >();

            for (int i = 0; i < 81; i++)
            {
                List <int> Poss = new List <int>();
                if (s.GetCellule(i / 9, i % 9) != 0)
                {
                    Poss.Add(10);
                }
                else
                {
                    foreach (int possibilities in s.GetPossibilities(i / 9, i % 9))
                    {
                        Poss.Add(possibilities);
                    }
                }
                LesPoss.Add(Poss);
            }
            return(LesPoss);
        }