Durchläufe durch Graphen SS12

(import debugging) (define amb-fail '*) (define initialize-amb-fail (lambda () (set! amb-fail (lambda () (error "amb" "It fails"))))) 
(initialize-amb-fail) (define-syntax amb (syntax-rules () ((amb alt ...) (let ((+prev-amb-fail amb-fail)) (call/cc (lambda (+sk) (call/cc 
(lambda (+fk) (set! amb-fail (lambda () (set! amb-fail +prev-amb-fail) (+fk 'fail))) (+sk alt))) ... (+prev-amb-fail))))))) (define-syntax 
bag-of (syntax-rules () ((bag-of e) (let ((+prev-amb-fail amb-fail) (+results '())) (if (call/cc (lambda (+k) (set! amb-fail (lambda () (+k 
#f))) (let ((+v e)) (set! +results (cons +v +results)) (+k #t)))) (amb-fail)) (set! amb-fail +prev-amb-fail) (reverse! +results))))) (define 
choice (lambda (ls) (eval (cons 'amb (map (lambda (x) (list 'quote x)) ls))))) (define multichoice (lambda (ls n) (if (= n 0) '() (let ((item 
(choice ls))) (cons item (multichoice (delete item ls) (- n 1))))))) (define delete (lambda (item ls) (cond ((null? ls) '()) ((eqv? (car ls) 
item) (cdr ls)) (else (cons (car ls) (delete item (cdr ls))))))) (define randomchoice (lambda (n) (letrec ((enumerate (lambda (i) (if (= i 0) 
'() (cons i (enumerate (- i 1))))))) (let ((numberlist (enumerate n))) (choice numberlist)))))

(define dfs (lambda (knoten besucht)
              (cond
                [(null? knoten) besucht]
                [else
                 (dfs (cdr knoten) (cons (car knoten) besucht))
                 (dfs (cdr knoten) besucht)])))

(dfs '(1 2 3) '())

;(trace dfs)
;(dfs '(1 2 3) '())

Durchläufe durch Graphen SS12

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