3) PostOrder traversal ans =[]defpostOrder(self, root):ifnotroot:returnpostOrder(root.left) postOrder(root.right)ans.append(root.val)postOrder(root)returnans Iterable method 1) Preorder traversal --- Just usestack. node-> left -> right defPreorder(self, root):ifnotroot:return[] ans, sta...
*/classSolution{public List<Integer>preorderTraversal(TreeNode root){List<Integer>result=newLinkedList<>();TreeNode current=root;TreeNode prev=null;while(current!=null){if(current.left==null){result.add(current.val);current=current.right;}else{// has left, then find the rightmost of left su...
postorder: left right root 今天重新做了buildTree 系列,从inorder, postorder中buildTree。 从inorder, preorder 中buildtree。 还有从preorder, postorder中buildtree。这三种方式都遵循着一个思想,就是他们是从recursion 建立的数组,那么inorder 就必须left root right, postorder 就必须left right root, 那么post...
前序Preorder: 先访问根节点,然后访问左子树,最后访问右子树。子树递归同理 中序Inorder: 先访问左子树,然后访问根节点,最后访问右子树. 后序Postorder:先访问左子树,然后访问右子树,最后访问根节点. classNode:def__init__(self,key):self.left=Noneself.right=Noneself.val=keydefprintInorder(root):ifroot...
Postorder 方法一:同上 classSolution {public: vector<int> postorderTraversal(TreeNode*root) { vector<int>res;if(root==NULL)returnres; unordered_map<TreeNode *,int> hash;//default value is 0;stack<TreeNode *>s({root});while(!s.empty()){ ...
Preorder, Inorder, and Postorder Iteratively Summarization[1] 1.Pre Order Traverse 1publicList<Integer>preorderTraversal(TreeNode root) {2List<Integer> result =newArrayList<>();3Deque<TreeNode> stack =newArrayDeque<>();4TreeNode p =root;5while(!stack.isEmpty() || p !=null) {6if(p !
Binary Tree Postorder Traversal 题目链接 题目要求: 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?
1 class TreeNode{ 2 char data; 3 TreeNode left; 4 TreeNode right; 5 static int leaf; 6 static boolean flag=true; 7 TreeNode (char c){ 8 data = c; 9 }
postorder classSolution{voidpushLeft(TreeNode*root,stack<pair<TreeNode*,bool>>&nodes){while(root){nodes.emplace(root,root->right==nullptr);root=root->left;}}public:vector<int>postorderTraversal(TreeNode*root){vector<int>res;if(!root)returnres;stack<pair<TreeNode*,bool>>nodes;pushLeft(root...
preorder用栈两三下就写完了 1vector<int> preorderTraversal(TreeNode *root) {2vector<int>nodes;3if(root == NULL)returnnodes;4stack<TreeNode *>tStack;5tStack.push(root);6while(!tStack.empty()){7TreeNode *top =tStack.top();8nodes.push_back(top->val);9tStack.pop();10if(top->right...