// Date: 07-11-22 08-04-25 Khu

namespace Problems
{
	class GcdProblemQAI : DivisibleProblemQAI
	{
		protected GcdSolution solution;

		protected int p, q, r, s;

		protected override void CheckSolvability ()
		{
			if (s == 0)
			{
				isDirectlySolvable = true;
				solution.Set(r);
			}
		}

		protected override void Divide ()
		{
			System.Diagnostics.Debug.Assert (!isDirectlySolvable, "precondition");
			int t = r % s;
			r = s;
			s = t;
		}

		public override Solution Solution () {return solution;} // no covariance!

		public int P {get {return p;}}
		public int Q {get {return q;}}

		public virtual void Set (int p, int q)
		{
			this.p = p;
			this.q = q;
			r = System.Math.Abs(p);
			s = System.Math.Abs(q);
			isDirectlySolvable = false;
			ComputeSolution();
		}

		public GcdProblemQAI ()
		{
			solution = new GcdSolution();
		}
	}
}