1.因为二叉搜索树的特性,将preorder数组排序,得到inorder。再将inorder的元素和下标用map存储起来,再对其进行递归。 2.利用二叉树的特性,初始化最小值,最大值,进行递归 3.用栈结构进行迭代。 classSolution {int[] preorder;intidx = 0; Map<Integer, Integer> map_inorder =newHashMap<>();publicTreeNode...
Given preorder and inorder traversal of a tree, construct the binary tree.解决思路首先确定根节点,然后确定左右子树的节点数目。依次递归即可。假设输入的序列均合法。程序1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 ...
public: TreeNode* build(vector<int>::iterator p_l,vector<int>::iterator p_r, vector<int>::iterator i_l,vector<int>::iterator i_r){ if(p_l-p_r>0)return NULL; TreeNode* current=new TreeNode(*p_l); auto k=find(i_l,i_r,current->val); int left_tree_n=k-i_l; current->...
private TreeNode helper(int[] preorder, int preL, int preR, int[] inorder, int inL, int inR, HashMap<Integer, Integer> map) { if(preL>preR || inL>inR) return null; TreeNode root = new TreeNode(preorder[preL]); int index = map.get(root.val); root.left = helper(preorder, ...
* TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */publicclassSolution{public TreeNodebuildTree(int[]preorder,int[]inorder){if(preorder==null||preorder.length==0)returnnull;if(inorder==null||inorder.length==0)returnnull;if(preorder.length!=inorder.length...
Given preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. 翻译:给定树的前序和中序遍历,构造二叉树。 注意: 树中不存在重复项。 思路:首先,你应该知道 前序遍历:根节点,左子树,右子树; ...
Construct Binary Tree from Preorder and Inorder Traversal 题目描述(中等难度) 根据二叉树的先序遍历和中序遍历还原二叉树。 解法一 递归 先序遍历的顺序是根节点,左子树,右子树。中序遍历的顺序是左子树,根节点,右子树。 所以我们只需要根据先序遍历得到根节点,然后在中序遍历中找到根节点的位置,它的左边就...
Given preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume thatduplicates do not existin the tree. 思路 主要是根据前序遍历和中序遍历的特点解决这个题目。 1、确定树的根节点。树根是当前树中所有元素在前序遍历中最先出现的元素。
题目: Given preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. 根据前序遍历和中序遍历结果构造二叉树。 思路分析: 分析二叉树前序遍历和中序遍历的结果我们发现: 二叉树前序遍历的第一个节点是根节点。 在中序遍历...
Can you solve this real interview question? Construct Binary Tree from Preorder and Postorder Traversal - Given two integer arrays, preorder and postorder where preorder is the preorder traversal of a binary tree of distinct values and postorder is the p