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...
结合代码。 publicList<Integer>inorderTraversal(TreeNoderoot){List<Integer>ans=newArrayList<>();Stack<TreeNode>stack=newStack<>();TreeNodecur=root;while(cur!=null||!stack.isEmpty()){//节点不为空一直压栈while(cur!=null){stack.push(cur);cur=cur.left;//考虑左子树}//节点为空,就出栈cur=s...
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{...
void in_order(TreeNode* root) { if (!root)return; in_order(root->left); res.push_back(root->val); in_order(root->right); } vector<int> inorderTraversal(TreeNode* root) { stack<TreeNode*>s; TreeNode *p = root; while (p || !s.empty()) { ...
This space is primarily used for the recursive call stack during the construction of the tree. Additionally, the inorder_index dictionary requires O(n) space, as it stores the index of each value in the inorder traversal list. Overall, the space usage is proportional to the number of nodes...
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...