public static void Sample_Einsteins_Puzzle()
{
//this example shows how to solve Einstein's puzzle
//go to http://en.wikipedia.org/wiki/Einstein's_Puzzle for more information on puzzle
var solutions = from n in ArrayExt.Enum <Nationality>().ToConstraintList(5)
from c in ArrayExt.Enum <HouseColor>().ToConstraintList(5)
from s in ArrayExt.Enum <Smoke>().ToConstraintList(5)
from d in ArrayExt.Enum <Drink>().ToConstraintList(5)
from p in ArrayExt.Enum <Pet>().ToConstraintList(5)
from i in 0.To(4).ToConstraintIndex()
where Constraint.AllDifferent(n)
where Constraint.AllDifferent(c)
where Constraint.AllDifferent(s)
where Constraint.AllDifferent(d)
where Constraint.AllDifferent(p)
where n[0] == Nationality.Norwegian
where d[2] == Drink.Milk
where (n[i] == Nationality.British) == (c[i] == HouseColor.Red)
where (n[i] == Nationality.German) == (s[i] == Smoke.Prince)
where (c[i] == HouseColor.Yellow) == (s[i] == Smoke.DunHill)
where (n[i] == Nationality.Danish) == (d[i] == Drink.Tea)
where (c[i] == HouseColor.Green) == (d[i] == Drink.Coffee)
where (s[i] == Smoke.BlueMaster) == (d[i] == Drink.Beer)
where (n[i] == Nationality.Swedish) == (p[i] == Pet.Dog)
where (s[i] == Smoke.PallMall) == (p[i] == Pet.Bird)
where (c[i] == HouseColor.Green) == (c[i + 1] == HouseColor.White)
where (p[i] == Pet.Cat) ? (s[i - 1] == Smoke.Blend || s[i + 1] == Smoke.Blend) : true
where ((p[i] == Pet.Horse) ? (s[i - 1] == Smoke.DunHill || s[i + 1] == Smoke.DunHill) : true)
where ((n[i] == Nationality.Norwegian) ? (c[i - 1] == HouseColor.Blue || c[i + 1] == HouseColor.Blue) : true)
where ((s[i] == Smoke.Blend) ? (d[i - 1] == Drink.Water || d[i + 1] == Drink.Water) : true)
select 0.To(4).Select(x =>
new
{
Nationality = n[x],
HouseColor = c[x],
Smoke = s[x],
Drink = d[x],
Pet = p[x]
});
//show results
Console.WriteLine("\tNationality\tHouseColor\tSmoke\t\tDrink\t\tPet");
Console.WriteLine(new string('-', 80));
solutions.First().ForEach((man, i) =>
Console.WriteLine("{0}\t{1}\t{2}\t{3}\t{4}\t{5}",
i + 1,
man.Nationality.ToString().PadRight(12),
man.HouseColor.ToString().PadRight(12),
man.Smoke.ToString().PadRight(12),
man.Drink.ToString().PadRight(12),
man.Pet.ToString().PadRight(12))
);
}
public static void Sample_River_Crossing()
{
//this example shows how to solve river crossing puzzle
//go to http://en.wikipedia.org/wiki/River_IQ_Test for more information on puzzle
//go to http://freeweb.siol.net/danej/riverIQGame.swf for the game
//create some variables
var allPeople = Cross.Thief | Cross.Police | Cross.Father | Cross.Mother | Cross.Son | Cross.Son2 | Cross.Daughter | Cross.Daughter2;
//STEP 1 - create combination of crossing
var crossing = ArrayExt.Enum <Cross>().Backtrack(
//Seed - number of people, and people
new { Length = 0, Value = (Cross)0 },
//Func - add number of people, add people
(current, item, i) => new { Length = current.Length + 1, Value = current.Value | item },
//Yield - must contains police, father, or mother
current => (current.Value & (Cross.Police | Cross.Father | Cross.Mother)) > 0
);
//thief-police is the same as police-thief, therefore skip police-thief
crossing.BacktrackingModel = BacktrackingModel.Combination;
//Answer can be 1 or 2 people on boat
crossing.ContinueOnYielded = true;
//Stop backtracking when there are more than 2 people
crossing.AppendBreak(current => current.Length > 2);
//Thief must be with police
crossing.AppendConstraint(current => current.Value == Cross.Thief,
current => item => item == Cross.Police);
//Father cannot be with daughter
crossing.AppendConstraint(current => current.Value == Cross.Father,
current => item => item != Cross.Daughter && item != Cross.Daughter2);
//Mother cannot be with son
crossing.AppendConstraint(current => current.Value == Cross.Mother,
current => item => item != Cross.Son && item != Cross.Son2);
//shows result
Console.WriteLine("below is combination of crossing");
crossing.SelectResults(c => c.Value).ForEach(c => Console.WriteLine(c));
Console.WriteLine();
//----------------------------------------------------------------------
//STEP 2 - create solutions based on combination of crossing
var solutions = crossing.SelectResults(c => c.Value).Backtrack(
//Seed - list of people on landA and landB
new
{
LandA = allPeople,
LandB = (Cross)0,
BoatOnLandA = true,
History = new[] { new { LandA = allPeople, BoatOnLandA = true } }
},
//Func - add/subtract crossing people to/from LandA, LandB
(last, item, i) => new
{
LandA = last.LandA ^ item,
LandB = last.LandB ^ item,
BoatOnLandA = !last.BoatOnLandA,
History = last.History.Append(new { LandA = last.LandA ^ item, BoatOnLandA = !last.BoatOnLandA })
},
//Yield - all people on LandB
last => last.LandB == allPeople
);
//Thief cannot be with others without police
solutions.AppendBreak(last =>
((last.LandA & (Cross.Thief | Cross.Police)) == Cross.Thief) && //no police
(last.LandA != Cross.Thief) //has others
);
solutions.AppendBreak(last =>
((last.LandB & (Cross.Thief | Cross.Police)) == Cross.Thief) && //no police
(last.LandB != Cross.Thief) //has others
);
//Son cannot be with mother without father
solutions.AppendBreak(last =>
((last.LandA & (Cross.Father | Cross.Mother)) == Cross.Mother) && //no father
((last.LandA & (Cross.Son | Cross.Son2)) > 0) //has sons
);
solutions.AppendBreak(last =>
((last.LandB & (Cross.Father | Cross.Mother)) == Cross.Mother) && //no father
((last.LandB & (Cross.Son | Cross.Son2)) > 0) //has sons
);
//Daughter cannot be with father without mother
solutions.AppendBreak(last =>
((last.LandA & (Cross.Father | Cross.Mother)) == Cross.Father) && //no mother
((last.LandA & (Cross.Daughter | Cross.Daughter2)) > 0) //has daugthers
);
solutions.AppendBreak(last =>
((last.LandB & (Cross.Father | Cross.Mother)) == Cross.Father) && //no mother
((last.LandB & (Cross.Daughter | Cross.Daughter2)) > 0) //has daugthers
);
//Must have people to cross
solutions.AppendConstraint(last => last.BoatOnLandA,
last => item => (last.LandA & item) == item);
solutions.AppendConstraint(last => !last.BoatOnLandA,
last => item => (last.LandB & item) == item);
//Check history
solutions.AppendConstraint(last => item => !last.History.Contains(new { LandA = last.LandA ^ item, BoatOnLandA = !last.BoatOnLandA }));
//show result
Console.WriteLine("Now start crossing");
solutions.SelectResults().First().History.ForEach(x =>
{
Console.WriteLine(x.LandA);
Console.WriteLine(allPeople ^ x.LandA);
Console.WriteLine("=============================================================");
});
}
public static void Sample_Einsteins_Puzzle()
{
//this example shows how to solve Einstein's puzzle
//go to http://en.wikipedia.org/wiki/Einstein's_Puzzle for more information on puzzle
//select combination of each person
var men = from n in ArrayExt.Enum <Nationality>()
from c in ArrayExt.Enum <HouseColor>()
where (n == Nationality.British) == (c == HouseColor.Red)
from s in ArrayExt.Enum <Smoke>()
where (n == Nationality.German) == (s == Smoke.Prince)
where (c == HouseColor.Yellow) == (s == Smoke.DunHill)
from d in ArrayExt.Enum <Drink>()
where (n == Nationality.Danish) == (d == Drink.Tea)
where (c == HouseColor.Green) == (d == Drink.Coffee)
where (s == Smoke.BlueMaster) == (d == Drink.Beer)
from p in ArrayExt.Enum <Pet>()
where (n == Nationality.Swedish) == (p == Pet.Dog)
where (s == Smoke.PallMall) == (p == Pet.Bird)
select new
{
Nationality = n,
HouseColor = c,
Smoke = s,
Drink = d,
Pet = p
};
//Generate solution
var solutions = men.Backtrack(5);
//New guy must not has same properties as persons in sequence
solutions.AppendConstraint(seq => seq.Any(),
seq => man => seq.All(x =>
x.Nationality != man.Nationality &&
x.HouseColor != man.HouseColor &&
x.Smoke != man.Smoke &&
x.Drink != man.Drink &&
x.Pet != man.Pet
)
);
//Norwegian lives in the first house.
solutions.AppendConstraint(seq => seq.Length == 0,
seq => man => man.Nationality == Nationality.Norwegian
);
//Guy who drinks milk lives in the third house
solutions.AppendConstraint(seq => seq.Length <= 2,
seq => man => (seq.Length == 2) == (man.Drink == Drink.Milk)
);
//White house is next to green house
solutions.AppendConstraint(seq => seq.Any(),
seq => man => (seq.Last().HouseColor == HouseColor.Green) == (man.HouseColor == HouseColor.White)
);
//Guy who pets cat is neighbor with guy who smokes Blend
solutions.AppendConstraint(seq => seq.Count(x => x.Pet == Pet.Cat || x.Smoke == Smoke.Blend) == 1,
seq => man => (man.Pet == Pet.Cat) || (man.Smoke == Smoke.Blend)
);
//Guy who pets horse is neighbor with guy who smokes DunHill
solutions.AppendConstraint(seq => seq.Count(x => x.Pet == Pet.Horse || x.Smoke == Smoke.DunHill) == 1,
seq => man => (man.Pet == Pet.Horse) || (man.Smoke == Smoke.DunHill)
);
//Norwegian is neighbor with guy lives in blue house
solutions.AppendConstraint(seq => seq.Count(x => x.Nationality == Nationality.Norwegian || x.HouseColor == HouseColor.Blue) == 1,
seq => man => (man.Nationality == Nationality.Norwegian) || (man.HouseColor == HouseColor.Blue)
);
//Guy who drinks water is neighbor with guy who smokes Blend
solutions.AppendConstraint(seq => seq.Count(x => x.Drink == Drink.Water || x.Smoke == Smoke.Blend) == 1,
seq => man => (man.Drink == Drink.Water) || (man.Smoke == Smoke.Blend)
);
//show results
Console.WriteLine("\tNationality\tHouseColor\tSmoke\t\tDrink\t\tPet");
Console.WriteLine(new string('-', 80));
solutions.First().ForEach((man, i) =>
Console.WriteLine("{0}\t{1}\t{2}\t{3}\t{4}\t{5}",
i + 1,
man.Nationality.ToString().PadRight(12),
man.HouseColor.ToString().PadRight(12),
man.Smoke.ToString().PadRight(12),
man.Drink.ToString().PadRight(12),
man.Pet.ToString().PadRight(12))
);
}
