已知中序和后序遍历，求前序遍历.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 inorder and postorder traversal, seeking preorder traversal. Stupid way is to draw out the binary tree, and then iterate based on a variety of different features to find, but also can be programmed to calculate.