diff options
| -rw-r--r-- | net/ricketyspace/sicp/two/fortytwo.scm | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/net/ricketyspace/sicp/two/fortytwo.scm b/net/ricketyspace/sicp/two/fortytwo.scm index 7ccf00e..e284591 100644 --- a/net/ricketyspace/sicp/two/fortytwo.scm +++ b/net/ricketyspace/sicp/two/fortytwo.scm @@ -3,7 +3,8 @@ ;;;; (define-module (net ricketyspace sicp two fortytwo) - #:export (safe?)) + #:export (safe? + adjoin-position)) (define (accumulate op initial sequence) (if (null? sequence) @@ -52,3 +53,8 @@ positions))) (if (null? in-same-diag) #f #t))) (not (or (same-row?) (same-diagonal?)))) + + +(define (adjoin-position new-row k rest-of-queens) + (let ((queen-at-k (cons new-row k))) + (append rest-of-queens (list queen-at-k)))) |