September Morn Update

Task/N-queens-problem/PowerBASIC/n-queens-problem-1.powerbasic

@@ -0,0 +1,46 @@
+#COMPILE EXE
+#DIM ALL
+
+SUB aux(n AS INTEGER, i AS INTEGER, a() AS INTEGER, _
+        u() AS INTEGER, v() AS INTEGER, m AS QUAD)
+
+    LOCAL j, k, p, q AS INTEGER
+    IF i > n THEN
+        INCR m
+        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
+                CALL 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
+
+FUNCTION PBMAIN () AS LONG
+    LOCAL n, i AS INTEGER
+    LOCAL m AS QUAD
+    IF COMMAND$(1) <> "" THEN
+        n = VAL(COMMAND$(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
+        CALL aux(n, 1, a(), u(), v(), m)
+        PRINT m
+    END IF
+END FUNCTION

Task/N-queens-problem/PowerBASIC/n-queens-problem-2.powerbasic

@@ -0,0 +1,47 @@
+#COMPILE EXE
+#DIM ALL
+
+FUNCTION PBMAIN () AS LONG
+    LOCAL n, i, j, k, p, q AS INTEGER
+    LOCAL m AS QUAD
+    IF COMMAND$(1) <> "" THEN
+        n = VAL(COMMAND$(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
+      1 IF i > n THEN
+            INCR m
+            FOR k = 1 TO n : PRINT a(k); : NEXT : PRINT
+            GOTO 4
+        END IF
+        j = i
+      2 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
+            INCR i
+            GOTO 1
+        END IF
+      3 INCR j : IF j <= n GOTO 2
+      4 DECR i : IF i = 0 THEN PRINT m : EXIT FUNCTION
+        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 3
+    END IF
+END FUNCTION

Task/N-queens-problem/PowerBASIC/n-queens-problem.powerbasic

@@ -1,40 +0,0 @@
-   defint a-z
-   option base 1
-   input "n=",n
-   dim a(n), s(n), u(4*n-2)
-   for i=1 to n: a(i)=i: next
-   for i=1 to 4*n-2: u(i)=0: next
-   m=0
-   i=1
-   r=2*n-1
-   goto 20
-10 s(i)=j
-   u(p)=1
-   u(q+r)=1
-   incr i
-20 if i>n goto 60
-   j=i
-30 z=a(i)
-   y=a(j)
-   p=i-y+n
-   q=i+y-1
-   a(i)=y
-   a(j)=z
-   if u(p)=0 and u(q+r)=0 goto 10
-40 incr j
-   if j<=n goto 30
-50 decr j
-   if j=i goto 70
-   swap a(i),a(j)
-   goto 50
-60 incr m
-   for k=1 to n: print a(k);: next: print
-70 decr i
-   if i=0 goto 80
-   p=i-a(i)+n
-   q=i+a(i)-1
-   j=s(i)
-   u(p)=0
-   u(q+r)=0
-   goto 40
-80 print m