#lang racket

(require "utils.rkt"
         rackunit)

(define (accumulate-n op init seqs)
  (if (null? (car seqs))
      '()
      (cons (accumulate op init (map car seqs))
            (accumulate-n op init (map cdr seqs)))))

(check equal? 
       (accumulate-n + 0 '((1 2 3) (4 5 6) (7 8 9) (10 11 12)))
       '(22 26 30))
       

(provide accumulate-n)