Zebra Puzzle solution using LINQ

ZebraPuzzleLinq.cs

#nullable enable

/*  Zebra Puzzle: https://en.wikipedia.org/wiki/Zebra_Puzzle
 *
 >  The following version of the puzzle appeared in Life International in 1962:
 >
 >       1. There are five houses.
 >       2. The Englishman lives in the red house.
 >       3. The Spaniard owns the dog.
 >       4. Coffee is drunk in the green house.
 >       5. The Ukrainian drinks tea.
 >       6. The green house is immediately to the right of the ivory house.
 >       7. The Old Gold smoker owns snails.
 >       8. Kools are smoked in the yellow house.
 >       9. Milk is drunk in the middle house.
 >      10. The Norwegian lives in the first house.
 >      11. The man who smokes Chesterfields lives in the house next to the man with the fox.
 >      12. Kools are smoked in the house next to the house where the horse is kept.
 >      13. The Lucky Strike smoker drinks orange juice.
 >      14. The Japanese smokes Parliaments.
 >      15. The Norwegian lives next to the blue house.
 >
 >  Now, who drinks water? Who owns the zebra?
 */

using System;
using System.Collections.Generic;
using System.Linq;
using static Color;
using static Nationality;
using static Pet;
using static Drink;
using static Smoke;

var houses =
    // Inspiration & credit:
    // https://rosettacode.org/wiki/Zebra_puzzle#%22Manual%22_solution_(Combining_Houses)
    from hs in new[]
    {
        // 1. There are five houses.
        from c in Enum.GetValues<Color>()
        from n in Enum.GetValues<Nationality>()
        from d in Enum.GetValues<Drink>()
        from s in Enum.GetValues<Smoke>()
        from p in Enum.GetValues<Pet>()
        select new House
        {
            Color       = c,
            Nationality = n,
            Drink       = d,
            Smoke       = s,
            Pet         = p
        }
        into e
        // 2. The Englishman lives in the red house.
        where e.Color is Red == e.Nationality is Englishman
        // 3. The Spaniard owns the dog.
        where e.Nationality is Spaniard == e.Pet is Dog
        // 4. Coffee is drunk in the green house.
        where e.Drink is Coffee == e.Color is Green
        // 5. The Ukrainian drinks tea.
        where e.Nationality is Ukranian == e.Drink is Tea
        // 7. The Old Gold smoker owns snails.
        where e.Smoke is OldGold == e.Pet is Snails
        // 8. Kools are smoked in the yellow house.
        where e.Smoke is Kools == e.Color is Yellow
        // 13. The Lucky Strike smoker drinks orange juice.
        where e.Smoke is LuckyStrike == e.Drink is OrangeJuice
        // 14. The Japanese smokes Parliaments.
        where e.Nationality is Japanese == e.Smoke is Parliaments
        select e
    }
    // Materialize before proceeding since the above sequence will be
    // reiterated multiple times.
    select hs.ToArray() into hs
    from h1 in hs
    // 10. The Norwegian lives in the first house.
    where h1 is { Nationality: Norwegian }
    from h3 in hs
    // 9. Milk is drunk in the middle house.
    where h3 is { Drink: Milk } && h3 ^ h1
    from h2 in hs
    // 15. The Norwegian lives next to the blue house.
    //
    // By logical deduction, since the Norwegian lives in the first
    // house, the second house must be blue.
    where h2 is { Color: Blue } && h2 ^ h1 && h2 ^ h3
    from h4 in hs
    where h4 ^ h1 && h4 ^ h2 && h4 ^ h3
    from h5 in hs
    where h5 ^ h1 && h5 ^ h2 && h5 ^ h3 && h5 ^ h4
    select new[] { h1, h2, h3, h4, h5 }
    into hs
    // 6. The green house is immediately to the right of the ivory house.
    where hs.Pairwise()
            .Any(pair => pair is ({ Color: Ivory }, { Color: Green }))
    // 11. The man who smokes Chesterfields lives in the house next to the man with the fox.
    where hs.Pairwise()
            .Any(pair => pair is ({ Smoke: Chesterfields }, { Pet: Fox })
                              or ({ Pet: Fox }, { Smoke: Chesterfields }))
    // 12. Kools are smoked in the house next to the house where the horse is kept.
    where hs.Pairwise()
            .Any(pair => pair is ({ Smoke: Kools }, { Pet: Horse })
                              or ({ Pet: Horse }, { Smoke: Kools }))
    from h in hs
    select h;

houses = houses.ToArray();

Console.WriteLine("| # | Color  | Nationality | Drink       | Smoke         | Pet    |");
Console.WriteLine("|---|--------|-------------|-------------|---------------|--------|");
foreach (var (h, i) in houses.Select((h, i) => (h, i + 1)))
    Console.WriteLine($"| {i} | {h.Color,-6} | {h.Nationality,-11} | {h.Drink,-11} | {h.Smoke,-13} | {h.Pet,-6} |");

Console.WriteLine();
Console.WriteLine($"Who drinks water? {houses.Single(h => h.Drink is Water).Nationality}");
Console.WriteLine($"Who owns the zebra? {houses.Single(h => h.Pet is Zebra).Nationality}");

public enum Color { Red, Green, Ivory, Yellow, Blue }
public enum Nationality { Englishman, Spaniard, Ukranian, Japanese, Norwegian }
public enum Pet { Dog, Snails, Fox, Horse, Zebra }
public enum Drink { Coffee, Tea, Milk, OrangeJuice, Water }
public enum Smoke { OldGold, Kools, Chesterfields, LuckyStrike, Parliaments }

sealed record House
{
    public required Color Color { get; init; }
    public required Nationality Nationality { get; init; }
    public required Drink Drink { get; init; }
    public required Smoke Smoke { get; init; }
    public required Pet Pet { get; init; }

    public static bool operator^(House a, House b)
        => a.Color       != b.Color
        && a.Nationality != b.Nationality
        && a.Drink       != b.Drink
        && a.Smoke       != b.Smoke
        && a.Pet         != b.Pet;
}

static class Extensions
{
    public static IEnumerable<(T, T)> Pairwise<T>(this IEnumerable<T> source)
    {
        using var e = source.GetEnumerator();
        if (!e.MoveNext())
            yield break;
        T b;
        for (var a = e.Current; e.MoveNext(); a = b)
            yield return (a, b = e.Current);
    }
}