Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of the corresponding binary tree. Input Spe…

题目 Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of the corresponding binary tree. Input…

1138 Postorder Traversal (25 分) Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of the corr…

https://pintia.cn/problem-sets/994805342720868352/problems/994805345078067200 Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number o…

Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of the corresponding binary tree. Input Spe…

题意:给出二叉树的前序序列后中序序列,输出其后序序列的第一个值. 思路:乍一看不就是前序+中序重建二叉树,然后后序遍历嘛!这么做当然不会有错,但是却没有真正领会本题的意图.本题并不是让我们输出后序序列,而只是输出后序序列的第一个值!考虑到后序遍历的顺序是:左子树->右子树->根结点,思考一下,如果根结点存在左子树,那么后序序列的第一个值肯定在左子树中,这个时候右子树就不是我们关心的了:如果没有左子树,那么后序序列的第一个值就在右子树中.因此,我们只需要在常规的“构建二叉树”的函数中递归找到这个…

Source: PAT A1138 Postorder Traversal (25 分) Description: Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder trav…

Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of the corresponding binary tree. Input Spe…

我们都知道,已知中序和后序的序列是可以唯一确定一个二叉树的. 初始化时候二叉树为:================== 中序遍历序列,           ======O=========== 后序遍历序列,           =================O 红色部分是左子树,黑色部分是右子树,O是根节点 如上图所示,O是根节点,由后序遍历可知, 根据这个O可以把找到其在中序遍历当中的位置,进而,知道当前这个根节点O的左子树的前序遍历和中序遍历序列的范围. 以及右子树的前序遍历和中序遍历…

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 给定一个二叉树,返回他的后序遍历的节点的values. 例如: 给定一个二叉树 {1,#,2,3}, 1 \ 2 / 3 返回 [3,2,1]. 笔记: 递归解决方案是微不足道的,你可以用迭代的方法吗? +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++…