否则,我们应访访问当前节点的右孩子(入栈)。 // C++ CODE: classSolution {public: vector<int> postorderTraversal(TreeNode*root) { stack<TreeNode*>s; vector<int>result;while(root){ s.push(root); root= root->left; }while(!s.empty()){ TreeNode* tmp =s.top();if(tmp->right){if(resu...
left(NULL), right(NULL) {}8* };9*/10/*常规层序遍历思想,每层入队结束压入一个空节点,作为标志*/11classSolution {12public:13vector<vector<int> > levelOrder(TreeNode *root) {14vector<vector<int>> vec_vec_tree;//创建空vector,
LeetCode 106. Construct Binary Tree from Inorder and Postorder Traversal Description Given inorder and postorder traversal of a tree, construct the binary tree. Note:You may assume that duplicates do not exist in the tree. For example, given inorder = [9,3,15,20,7]postorder = [9,15,7...
public void flatten(TreeNode root) { if(root==null) return; TreeNode curr = root; while(curr!=null){ //保存右子树, 后面用 TreeNode oldRight = curr.right; //左子树不为空, 执行一系列改变指向的操作 if(curr.left!=null){ //找到左子树的最右节点 TreeNode rightMost = curr.left; while(...
LeetCode 105. Construct Binary Tree from Preorder and Inorder Traversal Description Given preorder and inorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. For example, given ...
LeetCode Top 100 Liked Questions 236. Lowest Common Ancestor of a Binary Tree (Java版; Medium) 题目描述 Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined betw...
Can you solve this real interview question? Lowest Common Ancestor of a Binary Tree - Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia [https://en.wikipedia.org/wi
图片来源:https://leetcode.com/articles/binary-tree-right-side-view/ 对于时间复杂度来说,基本上都是O(n),因为要访问所有的点。 对于空间复杂度来说,BFS取决于扫描过程中每层的node数,就是树的宽度,而DFS取决于扫描过程中树的深度。最坏情况两个都是O(n)。
二维树状数组Binary Indexed Tree LeetCode题目:308. Range Sum Query 2D - Mutable Given a 2D matrixmatrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1,col1) and lower right corner (row2,col2). ...
* public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */publicclassSolution{publicTreeNodelowestCommonAncestor(TreeNode root,TreeNode p,TreeNode q){if(root.val-p.val>0&&root.val-q.val>0)returnlowestCommonAncestor(root.left,...