1/**2* Definition for a binary tree node.3* struct TreeNode {4* int val;5* TreeNode *left;6* TreeNode *right;7* TreeNode(int x) : val(x), left(NULL), right(NULL) {}8* };9*/10classSolution {11public:12vector<int> preorderTraversal(TreeNode*root) {13vector<int>rVec;14pr...
*/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与Inorder很相似,但是比Inorder复杂的地方是如何判断该节点的左右子树都已经访问过了,按照Inorder的写法左子树还是先被访问,没有问题,但是访问完左子树后不能直接访问当前节点,要判断当前节点的右子树是否已经被访问,如果没有访问则应该继续去访问右子树,最后再访问当前节点 1vector<int> postorderTraversal(T...
1vector<int> preorderTraversal(TreeNode*root) {2vector<int>rVec;3stack<TreeNode *>st;4TreeNode *tree =root;5while(tree || !st.empty())6{7if(tree)8{9st.push(tree);10rVec.push_back(tree->val);11tree = tree->left;12}13else14{15tree =st.top();16st.pop();17tree = tree-...
1#LeetCode 144. Binary Tree Preorder Traversal Given a binary tree, return the preorder traversal of its nodes' values. Note: Recursive solution is trivial, could you do it iteratively? Preorder: root, left, right Recursive version:/** ...
top-down代表在每次递归调用时,先访问该节点获得一些值,然后将这些值传递给children。top-down可以看作是preorder遍历,伪代码如下所示: 1. return specific value for null node 2. update the answer if needed // answer <-- params 3. left_ans = top_down(root.left, left_params) // left_params <...
同Construct Binary Tree from Inorder and Postorder Traversal(Python版) # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.left = left # self.right = right class Solution: def buildTree(self, pre...
inorder = [9,3,15,20,7] Return the following binary tree: 3 / \ 9 20 / \ 15 7 题目大意 根据一棵树的前序遍历与中序遍历构造二叉树。 注意: 你可以假设树中没有重复的元素。 解题思路 给出2 个数组,根据 preorder 和 inorder 数组构造一颗树。
Preorder traversal Inorder traversal Postorder traversalEssentially, all three traversals work in roughly the same manner. They start at the root and visit that node and its children. The difference among these three traversal methods is the order with which they visit the node itself versus ...
Preorder traversal Inorder traversal Postorder traversalEssentially, all three traversals work in roughly the same manner. They start at the root and visit that node and its children. The difference among these three traversal methods is the order with which they visit the node itself versus ...