2008-05-28から1日間の記事一覧

問題 2.32

;(subsets (list 1 2 3)) ;-> (() (3) (2) (2 3) (1) (1 3) (1 2) (1 2 3)) ;となるものを作ればいいのか? (define (append list1 list2) (if (null? list1) list2 (cons (car list1) (append (cdr list1) list2)))) (define (subsets s) (if (null? s) (li…

問題 2.31

(define (square x) (* x x)) (define (square-tree tree) (tree-map square tree)) ;高階手続き無しの形。 (define (tree-map f tree) (cond ((null? tree) null) ((not (pair? tree)) (f tree)) (else (cons (tree-map f (car tree)) (tree-map f (cdr tre…

問題 2.30

(define (square x) (* x x)) ;高階手続き無しの形。 (define (square-tree tree) (cond ((null? tree) null) ((not (pair? tree)) (square tree)) (else (cons (square-tree (car tree)) (square-tree (cdr tree)))))) (square-tree (list 1 (list 2 (list …