Exercise 1.12

文責:@ayato_p

パスカルの三角形の要素を求める

(define (pascal row col)
  (cond
   ((or (< col 0) (< row 0)) 0)
   ((> col row) 0)
   ((or (= row 1)(= col 1)) 1)
   (else
    (+ (pascal (- row 1) (- col 1))
       (pascal (- row 1) col)))))