sameDigits()

sameDigits.linq

<Query Kind="Program" />

void Main()
{
	sameDigits(1);
	sameDigits(10);
	sameDigits(251894);
	sameDigits(251895);
}

HashSet<char> GetDigits(long n) => new HashSet<char>(n.ToString().ToCharArray().Distinct().OrderBy(c => c).ToArray());

bool Eq<T>(HashSet<T> one, HashSet<T> two)
{
	if (one is null && two != null || one != null && two is null) return false;
	if (one.Count != two.Count) return false;
	
	return one.Intersect(two).Count() == one.Count;
}

void sameDigits(long n)
{
	var n3 = n * n * n;
	var nSet = GetDigits(n);
	var n3Set = GetDigits(n3);
	var eq = Eq(nSet, n3Set);

	Console.WriteLine($"sameDigits({n}) // {eq}");
}