vector<int> preorderTraversal(TreeNode *root) { stack<TreeNode*>StackTree; vector<int>data;if(root==NULL)returndata; StackTree.push(root);while(!StackTree.empty()) { TreeNode*CurrentNode=StackTree.top(); StackTree.pop(); data.push_back(CurrentNode->val);if(CurrentNode->right!=NULL) ...
Recursive solution ---O(n)time andO(n)space (considering the spaces of call stack); Morris traversal ---O(n)time andO(1)space!!! Iterative solution using stack: 1vector<int> preorderTraversal(TreeNode*root) {2vector<int>nodes;3stack<TreeNode*>toVisit;4TreeNode* curNode =root;5while...
push(cur.right); stack.push(cur.left); } return list; } 解法三 Morris Traversal 上边的两种解法,空间复杂度都是O(n),利用 Morris Traversal 可以使得空间复杂度变为 O(1)。 它的主要思想就是利用叶子节点的左右子树是 null ,所以我们可以利用这个空间去存我们需要的节点,详细的可以参考 94 题 中序...
vector<int> preorderTraversal(TreeNode * root) { // write your code here vector<int> result; if (root == nullptr) { return result; } stack<TreeNode *> nodeStack; nodeStack.push(root); // 初始化时候,根节点入栈 TreeNode * cur = root; while (!nodeStack.empty()) // 循环只需要判...
binary-tree-preorder-traversal 题意:前序遍历二叉树 前序遍历 根->左子树->右子树 先递归解法: classSolution {public: vector<int> preorderTraversal(TreeNode *root) { vector<int>res; position(root, res);returnres; }voidposition(TreeNode *root, vector<int> &res){if(root){...
INORDER AND PREORDER TRAVERSAL and DISPLAY OF EXISTING BINARY TREE IN COMPUTER MEMORYP K KumaresanJournal of Harmonized Research
* public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */publicclassSolution{publicList<Integer>preorderTraversal(TreeNoderoot){List<Integer>ret=newArrayList<Integer>();if(root==null){returnret;}Stack<TreeNode>st=newStack<TreeNo...
# Definition for a binary tree node.# class TreeNode(object):# def __init__(self, x):# self.val = x# self.left = None# self.right = NoneclassSolution(object):defpreorderTraversal(self,root):""" :type root: TreeNode :rtype: List[int] ...
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...
Given a binary tree, return thepreordertraversal of its nodes' values. Example: [1,null,2,3] [1,2,3] Follow up: Recursive solution is trivial, could you do it iteratively? 一般我们提到树的遍历,最常见的有先序遍历,中序遍历,后序遍历和层序遍历,它们用递归实现起来都非常的简单。而题目的要求...