Question 590. N-ary Tree Postorder Traversal Solution 题目大意:后序遍历一个树 思路: 1)递归 2)迭代 Java实现(递归): public List<Integer> postorder(Node root) { List<Integer> ansList = new ArrayList<>(); recursivePostorder(root, ansList); return ansList; } void…

题目: Given a binary tree, return the postorder traversal 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? 题解: 递归方法代码:          ArrayList<Integer…

原题链接:https://oj.leetcode.com/problems/binary-tree-postorder-traversal/ 题目大意:后序遍历二叉树 解题思路:后序遍历二叉树的步骤:后序遍历二叉树的左子树,后序遍历二叉树的右子树,訪问根结点. 非递归实现时,用一个栈模拟遍历过程.由于訪问完左子树后訪问右子树.栈中元素要起到转向訪问其右子树的作用,可是不能像先序和中序遍历那样出栈就可以,由于根结点时最后訪问的.那么什么时候出栈呢?我们须要一个指针pre来记录前一次訪问的结点.假设…

590. N叉树的后序遍历 590. N-ary Tree Postorder Traversal 题目描述 给定一个 N 叉树,返回其节点值的后序遍历. LeetCode590. N-ary Tree Postorder Traversal 例如,给定一个 3 叉树: 返回其后序遍历: [5,6,3,2,4,1]. 说明: 递归法很简单,你可以使用迭代法完成此题吗? Java 实现 Iterative Solution import java.util.LinkedList; import j…

145. 二叉树的后序遍历 145. Binary Tree Postorder Traversal 题目描述 给定一个二叉树,返回它的 后序 遍历. LeetCode145. Binary Tree Postorder Traversal 示例: 输入: [1,null,2,3] 1 \ 2 / 3 输出: [3,2,1] 进阶: 递归算法很简单,你可以通过迭代算法完成吗? Java 实现 Iterative Solution import java.util.LinkedList; impo…

Given an n-ary tree, return the postorder traversal of its nodes' values. For example, given a 3-ary tree: Return its postorder traversal as: [5,6,3,2,4,1]. Note: Recursive solution is trivial, could you do it iteratively? 这道题让我们求N叉树的后序遍历,由于有了之前那道Bin…

145. Binary Tree Postorder Traversal Total Submissions: 271797 Difficulty: Hard 提交网址: https://leetcode.com/problems/binary-tree-postorder-traversal/ Given a binary tree, return the postorder traversal of its nodes' values. For example:Given binary tr…

problem 590. N-ary Tree Postorder Traversal 参考 1. Leetcode_easy_590. N-ary Tree Postorder Traversal; 完…

题目:Binary Tree Postorder Traversal 二叉树的后序遍历,题目要求是采用非递归的方式,这个在上数据结构的课时已经很清楚了,二叉树的非递归遍历不管采用何种方式,都需要用到栈结构作为中转,代码很简单,见下: struct TreeNode { int val; TreeNode* left; TreeNode* right; TreeNode(int x): val(x), left(NULL),right(NULL) {} }; vector<int> preord…

Binary Tree Postorder Traversal Given a binary tree, return the postorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3},   1    \     2    /   3return [3,2,1]. Note: Recursive solution is trivial, could you do it iteratively…