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 =newHash
node->left = dfs(l +1, i -1, p); node->right =dfs(i, r, p);returnnode; } TreeNode* bstFromPreorder(vector<int>&preorder) {returndfs(0, preorder.size() -1, preorder); } }; 2. O(N) classSolution {public:inti =0; TreeNode* bstFromPreorder(vector<int>& A,intbound =...
current->right=build(p_l+left_tree_n+1,p_r,k+1,i_r); return current; } TreeNode* buildTree(vector<int>& preorder, vector<int>& inorder) { if(preorder.empty())return NULL; return build(preorder.begin(),preorder.end()-1,inorder.begin(),inorder.end()-1); } }; 1. 2. ...
//preorder_left+1---preorder_left+left_size是preorder的左子树位置,对应inordered左子树位置为inorder_left---inorder_root-1。preorder边界是来确定左子树的左右子树边界,后面的inorder边界来获取左子树大小,知道左子树大小也知道了右子树大小。 root->left = bT(preorder,inorder,preorder_left+1,preorde...
Preorder traversal Visit root node Visit all the nodes in the left subtree Visit all the nodes in the right subtree display(root->data) preorder(root->left) preorder(root->right) Postorder traversal Visit all the nodes in the left subtree Visit all the nodes in the right subtree Visit th...
public List<Integer> preorderTraversal(TreeNode root) { List<Integer> list = new ArrayList<>(); preorderTraversalHelper(root, list); return list; } private void preorderTraversalHelper(TreeNode root, List<Integer> list) { if (root == null) { return; } list.add(root.val); preorderTrav...
Can you solve this real interview question? Binary Tree Preorder Traversal - Given the root of a binary tree, return the preorder traversal of its nodes' values. Example 1: Input: root = [1,null,2,3] Output: [1,2,3] Explanation: [https://assets.l
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...
To understand the preorder traversal better, consider the following binary search tree ? The traversal will start from the root node A and prints it. From there it visits its left subtree B and prints it. And again will print left subtree D. And again print the H subtree. Since, H does...
Memory Usage: 35.8 MB, less than 99.68% of Java online submissions for Construct Binary Search Tree from Preorder Traversal. 网友最佳解法1,最优解法是以插入方式去拼出整个树 public TreeNode bstFromPreorder(int[] preorder) { TreeNode root = new TreeNode(preorder[0]); for (int i = 1; ...