Approach 2: Iterating method using Stack 迭代(基于栈) The strategy is very similiar to the first method, the different is using stack. 伪代码如下(摘录自Wikipedia Tree_traversal) iterativeInorder(node) parentStack=empty stackwhile(notparentStack.isEmpty()ornode ≠ null)if(node ≠ null) parent...
A binary tree isthreadedby making all right child pointers that would normally be null point to the inorder successor of the node (ifit exists), and all left child pointers that would normally be null point to the inorder predecessor of the node. 就是说线索二叉树实际上是把所有原本为空的...
public List<Integer> inorderTraversal(TreeNode root) { List<Integer> ans = new ArrayList<>(); Stack<TreeNode> stack = new Stack<>(); TreeNode cur = root; while (cur != null || !stack.isEmpty()) { //节点不为空一直压栈 while (cur != null) { stack.push(cur); cur = cur.le...
vector<int> inorderTraversal(TreeNode* root) { vector<int> res; stack<TreeNode*> treeroot; while(root!=NULL||!treeroot.empty()) { while(root!=NULL) { treeroot.push(root); root=root->left; } root = (); treeroot.pop(); res.push_back(root->val); root = root->right; } retu...
Preorder traversal starts printing from the root node and then goes into the left and right subtrees, respectively, while postorder traversal visits the root node in the end. #include<iostream>#include<vector>using std::cout;using std::endl;using std::string;using std::vector;structTreeNode{...
Leetcode 之Binary Tree Inorder Traversal(43) 树的中序遍历。先不断压入左结点至末尾,再访问,再压入右结点。注意和先序遍历的比较 vector<int> inorderTraversal(TreeNode *root) { vector<int>result; stack<TreeNode *>s; TreeNode*p =root;while(!s.empty() || p !=nullptr)...
Given a binary tree, return the inorder traversal of its nodes' values. 给定一个二叉树,返回中序遍历后所有节点的值。 Example: Input: [1,null,2,3] 1 \ 2 / 3 Output: [1,3,2] Follow up: Recursive solution is trivial, could you do it iteratively? 追加问题:可以不用递归,而是用遍历实...
Binary Tree Level Order Traversal 二叉树层序遍历 Example Givenbinary tree[3,9,20,null,null,15,7],3/\920/\157returnits level order traversalas:[[3],[9,20],[15,7]] BFS方法 var levelOrder=function(root){if(!root)return[]conststack=[root]constres=[]while(stack.length){constlen=stack...
*/publicclassSolution{public List<Integer>inorderTraversal(TreeNode root){ArrayList<Integer>ret=newArrayList<Integer>();if(root==null)returnret;Stack<TreeNode>s=newStack<TreeNode>();TreeNode node=root;while(node!=null){s.push(node);node=node.left;}while(!s.isEmpty()){TreeNode curr=s.pop...
Binary tree traversal: Preorder, Inorder, and Postorder In order to illustrate few of the binary tree traversals, let us consider the below binary tree: Preorder traversal: To traverse a binary tree in Preorder, following operations are carried-out (i) Visit the root, (ii) Traverse the le...