/// <summary>
/// Truth tables for logical expressions.
/// Write a predicate table/3 which prints the truth table of a given logical expression in two variables.
/// </summary>
/// <param name="func"></param>
/// <returns></returns>
public static List <(bool, bool, bool)> _3_01(Func <bool, bool, bool> func)
{
var booleans = new List <bool> {
true, false
};
return(booleans.SelectMany(a => Lists._1_05(booleans).Select(b => (a, b, func(a, b)))).ToList());
}
/// <summary>
/// Gray code.
/// An n-bit Gray code is a sequence of n-bit strings constructed according to certain rules. For example,
/// n = 1: C(1) = ['0','1'].
/// n = 2: C(2) = ['00','01','11','10'].
/// n = 3: C(3) = ['000','001','011','010','110','111','101','100'].
/// Find out the construction rules and write a predicate with the following specification:
/// % gray(N,C) :- C is the N-bit Gray code
/// </summary>
/// <param name="number"></param>
/// <returns></returns>
public static List <string> _3_04(int number)
{
if (number == 1)
{
return(new List <string> {
"0", "1"
});
}
var left = _3_04(number - 1);
var right = Lists._1_05(left);
return(left.Select(i => "0" + i).Concat(right.Select(i => "1" + i)).ToList());
}