摘要： 本答案部分参考SICP 解题集byhuangz，和SICP学习笔记和习题解答byKelvin。2.2.2层次性结构计算叶节点用这个递归方程计算就好了：(leaves tree) = (leaves (car tree)) + (leaves (cdr tree)),(leaves leave) = ... 阅读全文