classSolution {public: vector<int> postorderTraversal(TreeNode *root) { vector<int>res;if(root==NULL)returnres; stack<pair<TreeNode*,int>>s;intunUsed; s.push(make_pair(root,1));while(!s.empty()) { root=s.top().
* Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * };*/classSolution {public: vector<int> postorderTraversal(TreeNode*root) { vector<int>res; stack<TreeNode*>st...
publicList<Integer>postorderTraversal(TreeNoderoot){List<Integer>list=newArrayList<>();Stack<TreeNode>stack=newStack<>();Set<TreeNode>set=newHashSet<>();TreeNodecur=root;while(cur!=null||!stack.isEmpty()){while(cur!=null&&!set.contains(cur)){stack.push(cur);cur=cur.left;}cur=stack.p...
给定一个二叉树,返回它的后序遍历。 示例: 输入:[1,null,2,3] 1 \ 2 / 3输出:[3,2,1] 1. 2. 3. 4. 5. 6. 7. 8. 进阶:递归算法很简单,你可以通过迭代算法完成吗? DFS 今天这道题比较简单,直接DFS就可以了。 Code def postorderTraversal(self, root: TreeNode) -> List[int]: def dfs...
PAT (Advanced Level) Practice 1138 Postorder Traversal (25 分) 凌宸1642 题目描述: Suppose that all the keys in a binary tree are distinct positive integers. Given the preorder and inorder traversal sequences, you are supposed to output the first number of the postorder traversal sequence of ...
binary-tree-postorder-traversal title: binary-tree-postorder-traversal 描述 Given a binary tree, return thepostordertraversal of its nodes' values. For example: Given binary tree{1,#,2,3}, 1 \ 2 / 3 return[3,2,1]. Note:Recursive solution is trivial, could you do it iteratively?
Solution{public:vector<int>postorderTraversal(TreeNode*root){vector<int>result;stack<TreeNode*>st;TreeNode*p=root,*q=NULL;do{while(p)st.push(p),p=p->left;q=NULL;while(!st.empty()){p=st.top();st.pop();if(p->right==q)//右子树为空或者已经访问{result.push_back(p->val);q=p...
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...
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Given a binary tree, return thepostordertraversal of its nodes' values. For example: Given binary tree{1,#,2,3}, 1 \ 2 / 3 return[3,2,1]. Note:Recursive solution is trivial, could you do it iteratively? ++++++++++++++++++++++++++++++++++++++++++ 【二叉树遍历模版】后...