depth-first-search

dfs.scm

(define (dfs tree)
  (display (car tree))
  (newline)
  (let loop ((xs (cdr tree)))
    (if (not (null? xs))
        (begin
          (dfs (car xs))
          (loop (cdr xs))))))

(dfs '(1 (2 (3 (4)) (5) (6)) (7 (8 (9) (10) (11)) (12 (13 (14))))))