テーブル表現 (define (lookup key table) (let ( (record (assoc key (cdr table))) ) (if record (cdr record) #f) ) ) ; キーチェック (define (assoc key records) (cond ((null? records) #f) ((equal? key (caar records)) (car records)) (else (asso…

キューの実装 (define (front-ptr queue) (car queue)) (define (rear-ptr queue) (cdr queue)) (define (set-front-ptr! queue item) (set-car! queue item)) (define (set-rear-ptr! queue item) (set-cdr! queue item)) (define (empty-queue? queue) (nu…