search through a tree and return true if a node is present more than once

[kiyo_hiko]

気が向いたら読む 全然関係ないけどカウントする何かを書いたのでメモする (defun count-tree (x xs) (cond ((null xs) 0) ((consp (car xs)) (+ (count-tree x (car xs)) (count-tree x (cdr xs)))) (t (+ (if (equal x (car xs)) 1 0) (count-tree x (cdr xs))))))