Initial data commit

Task/Power-set/VBA/power-set.vba

@@ -0,0 +1,46 @@
+Option Base 1
+Private Function power_set(ByRef st As Collection) As Collection
+    Dim subset As Collection, pwset As New Collection
+    For i = 0 To 2 ^ st.Count - 1
+        Set subset = New Collection
+        For j = 1 To st.Count
+            If i And 2 ^ (j - 1) Then subset.Add st(j)
+        Next j
+        pwset.Add subset
+    Next i
+    Set power_set = pwset
+End Function
+Private Function print_set(ByRef st As Collection) As String
+    'assume st is a collection of collections, holding integer variables
+    Dim s() As String, t() As String
+    ReDim s(st.Count)
+    'Debug.Print "{";
+    For i = 1 To st.Count
+        If st(i).Count > 0 Then
+            ReDim t(st(i).Count)
+            For j = 1 To st(i).Count
+                Select Case TypeName(st(i)(j))
+                    Case "Integer": t(j) = CStr(st(i)(j))
+                    Case "Collection": t(j) = "{}" 'assumes empty
+                End Select
+            Next j
+            s(i) = "{" & Join(t, ", ") & "}"
+        Else
+            s(i) = "{}"
+        End If
+    Next i
+    print_set = "{" & Join(s, ", ") & "}"
+End Function
+Public Sub rc()
+    Dim rcset As New Collection, result As Collection
+    For i = 1 To 4
+        rcset.Add i
+    Next i
+    Debug.Print print_set(power_set(rcset))
+    Set rcset = New Collection
+    Debug.Print print_set(power_set(rcset))
+    Dim emptyset As New Collection
+    rcset.Add emptyset
+    Debug.Print print_set(power_set(rcset))
+    Debug.Print
+End Sub