已知前序、中序遍历，求后序遍历.比较笨的方法是画出来二叉树，然后根据各种遍历不同的特性来求，也可以编程求出.-Known pre-order, preorder, seeking after preorder. Stupid way is to draw out the tree, and then iterate based on a variety of different features to find, but also can be programmed to calculate.