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-rw-r--r--test/q.scm69
1 files changed, 69 insertions, 0 deletions
diff --git a/test/q.scm b/test/q.scm
new file mode 100644
index 0000000..498cfad
--- /dev/null
+++ b/test/q.scm
@@ -0,0 +1,69 @@
+(define (shl bits)
+ (define len (vector-length bits))
+ (define res (make-vector len))
+ (define (copy i)
+ (if (= i (- len 1))
+ #t
+ (and
+ (vector-set! res i
+ (vector-ref bits (+ i 1)))
+ (copy (+ i 1)))))
+ (copy 0)
+ (set! copy '())
+ (vector-set! res (- len 1) #f)
+ res)
+
+(define (shr bits)
+ (define len (vector-length bits))
+ (define res (make-vector len))
+ (define (copy i)
+ (if (= i (- len 1))
+ #t
+ (and
+ (vector-set! res (+ i 1)
+ (vector-ref bits i))
+ (copy (+ i 1)))))
+ (copy 0)
+ (set! copy '())
+ (vector-set! res 0 #f)
+ res)
+
+(define (empty-bits len) (make-vector len #f))
+(define vs vector-set!)
+(define vr vector-ref)
+(define res 0)
+(define (queen n)
+
+ (define (search l m r step)
+ (define (col-iter c)
+ (if (= c n)
+ #f
+ (and
+ (if (and (eq? (vr l c) #f)
+ (eq? (vr r c) #f)
+ (eq? (vr m c) #f))
+ (and
+ (vs l c #t)
+ (vs m c #t)
+ (vs r c #t)
+ ((lambda () (search l m r (+ step 1)) #t))
+ (vs l c #f)
+ (vs m c #f)
+ (vs r c #f))
+ )
+ (col-iter (+ c 1))
+ )))
+ (set! l (shl l))
+ (set! r (shr r))
+ (if (= step n)
+ (set! res (+ res 1))
+ (col-iter 0)))
+ ; (set! col-iter '()))
+
+ (search (empty-bits n)
+ (empty-bits n)
+ (empty-bits n)
+ 0)
+ res)
+
+(display (queen 8))