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…

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…

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…

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…

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…

树(23) 备注 1004 Counting Leaves   1020 Tree Traversals   1043 Is It a Binary Search Tree 判断BST,BST的性质 1053 Path of Equal Weight   1064 Complete Binary Search Tree 完全二叉树的顺序存储,BST的性质 1066 Root of AVL Tree 构建AVL树,模板题,需理解记忆 1079 Total Sales of Supply Chain…

二叉树 PAT (Advanced Level) Practice 二叉树 相关题 目录 <算法笔记> 重点摘要 1020 Tree Traversals (25) 1086 Tree Traversals Again (25) 1102 Invert a Binary Tree (25) 1119 Pre- and Post-order Traversals (30) 1127 ZigZagging on a Tree (30) 1138 Postorder Traversal (25) 1…

PAT甲级1119. Pre- and Post-order Traversals 题意: 假设二叉树中的所有键都是不同的正整数.一个唯一的二进制树可以通过给定的一对后序和顺序遍历序列来确定,也可以通过预序和顺序遍历序列来确定.然而,如果仅给出了后序和预序遍历序列,则相应的树可能不再是唯一的. 现在给出一对postorder和preorder遍历序列,你应该输出树的相应的顺序遍历序列.如果树不是唯一的,只需输出任何一个树. 输入规格: 每个输入文件包含一个测试用例.对于每种情况,第一行给出正整数…