Solving https://news.ycombinator.com/item?id=8486278 with the Decider constraint solver tool

gistfile1.cs

using Decider.Csp.BaseTypes;
using Decider.Csp.Integer;
using System;
using System.Collections.Generic;

namespace Chickens
{
    class Program
    {
        static void Main(string[] args)
        {
            var x1 = new VariableInteger("x1", 1, 9);
            var x2 = new VariableInteger("x2", 1, 9);
            var y1 = new VariableInteger("y1", 1, 15);
            var y2 = new VariableInteger("y2", 1, 15);
            var z1 = new VariableInteger("z1", 1, 25);
            var z2 = new VariableInteger("z2", 1, 25);

            var p1 = new VariableInteger("p1", 1, 500);
            var p2 = new VariableInteger("p2", 1, 500);

            var constraints = new List<ConstraintInteger>
                {
                    new ConstraintInteger(p1 > p2),
                    new ConstraintInteger(x1 > y1),
                    new ConstraintInteger(y1 > z1),
                    new ConstraintInteger(x1 * p1 + x2 * p2 == 3500),
                    new ConstraintInteger(y1 * p1 + y2 * p2 == 3500),
                    new ConstraintInteger(z1 * p1 + z2 * p2 == 3500),
                    new ConstraintInteger(x1 + x2 == 10),
                    new ConstraintInteger(y1 + y2 == 16),
                    new ConstraintInteger(z1 + z2 == 26),
                };

            IState<int> state = new StateInteger(new[] { p1, p2, x1, x2, y1, y2, z1, z2 }, constraints);

            StateOperationResult result;
            state.StartSearch(out result);

            if (result == StateOperationResult.Solved)
            {
                Console.WriteLine("x1:\t{0}", x1);
                Console.WriteLine("x2:\t{0}", x2);
                Console.WriteLine("y1:\t{0}", y1);
                Console.WriteLine("y2:\t{0}", y2);
                Console.WriteLine("z1:\t{0}", z1);
                Console.WriteLine("z2:\t{0}", z2);
                Console.WriteLine();
                Console.WriteLine("p1:\t{0}", p1);
                Console.WriteLine("p2:\t{0}", p2);
            }

            Console.WriteLine("Done.");
            Console.ReadKey();
        }
    }
}