Data commit

Task/Lah-numbers/Visual-Basic-.NET/lah-numbers.vb

@@ -0,0 +1,57 @@
+Imports System.Numerics
+
+Module Module1
+
+    Function Factorial(n As BigInteger) As BigInteger
+        If n = 0 Then
+            Return 1
+        End If
+
+        Dim res As BigInteger = 1
+        While n > 0
+            res *= n
+            n -= 1
+        End While
+        Return res
+    End Function
+
+    Function Lah(n As BigInteger, k As BigInteger) As BigInteger
+        If k = 1 Then
+            Return Factorial(n)
+        End If
+        If k = n Then
+            Return 1
+        End If
+        If k > n Then
+            Return 0
+        End If
+        If k < 1 OrElse n < 1 Then
+            Return 0
+        End If
+        Return (Factorial(n) * Factorial(n - 1)) / (Factorial(k) * Factorial(k - 1)) / Factorial(n - k)
+    End Function
+
+    Sub Main()
+        Console.WriteLine("Unsigned Lah numbers: L(n, k):")
+        Console.Write("n/k ")
+        For Each i In Enumerable.Range(0, 13)
+            Console.Write("{0,10} ", i)
+        Next
+        Console.WriteLine()
+
+        For Each row In Enumerable.Range(0, 13)
+            Console.Write("{0,-3}", row)
+            For Each i In Enumerable.Range(0, row + 1)
+                Dim l = Lah(row, i)
+                Console.Write("{0,11}", l)
+            Next
+            Console.WriteLine()
+        Next
+        Console.WriteLine()
+
+        Console.WriteLine("Maximum value from the L(100, *) row:")
+        Dim maxVal = Enumerable.Range(0, 100).Select(Function(a) Lah(100, a)).Max
+        Console.WriteLine(maxVal)
+    End Sub
+
+End Module