Initial data commit

Task/N-queens-problem/FreeBASIC/n-queens-problem-3.basic

@@ -0,0 +1,43 @@
+Dim As Integer n, i, j, k, p, q
+Dim m As LongInt = 0
+
+If Command(1) <> "" Then
+    n = CInt(Command(1))
+    ReDim a(1 To n) As Integer
+    ReDim s(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
+    i = 1
+L1: If i > n Then
+        m += 1
+        For k = 1 To n : Print a(k); : Next : Print
+        Goto L4
+    End If
+    j = i
+L2: 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
+        s(i) = j
+        i += 1
+        Goto L1
+    End If
+L3: j += 1 : If j <= n Goto L2
+L4: i -= 1 : If i = 0 Then Print m : End
+    j = s(i)
+    k = a(i) : a(i) = a(j) : a(j) = k
+    p = i - k + n
+    q = i + k - 1
+    u(p) = 1 : v(q) = 1
+    Goto L3
+End If