Initial data commit

Task/N-queens-problem/FreeBASIC/n-queens-problem-2.basic

@@ -0,0 +1,41 @@
+Sub aux(n As Integer, i As Integer, a() As Integer, _
+        u() As Integer, v() As Integer, ByRef m As LongInt)
+
+    Dim As Integer j, k, p, q
+    If i > n Then
+        m += 1
+        For k = 1 To n : Print a(k); : Next : Print
+    Else
+        For j = i To n
+            k = a(j)
+            p = i - k + n
+            q = i + k - 1
+            If u(p) And v(q) Then
+                u(p) = 0 : v(q) = 0
+                a(j) = a(i) : a(i) = k
+                aux(n, i + 1, a(), u(), v(), m)
+                u(p) = 1 : v(q) = 1
+                a(i) = a(j) : a(j) = k
+            End If
+        Next
+    End If
+End Sub
+
+Dim As Integer n, i
+Dim m As LongInt = 1
+If Command(1) <> "" Then
+    n = CInt(Command(1))
+    ReDim a(1 To n) As Integer
+    ReDim u(1 To 2 * n - 1) As Integer
+    ReDim v(1 To 2 * n - 1) As Integer
+    For i = 1 To n
+        a(i) = i
+    Next
+    For i = 1 To 2 * n - 1
+        u(i) = 1
+        v(i) = 1
+    Next
+    m = 0
+    aux(n, 1, a(), u(), v(), m)
+    Print m
+End If