题目: Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its level order traversal as: [ [3], [9,20], [15,7]…

Binary Tree Level Order Traversal 本题收获: 1.vector<vector<int>>的用法 vector<vector<int> >注意<int>后面的空格,vector<vector<int>>表示的是二位向量. 输出格式(后面代码),不知道大小时,在vector中用push_back(vector<int>()) 2.树用迭代 题目: Given a binary tr…

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 给定一个二叉树,返回他的层次遍历的节点的values.(提示,从左到右,一层一层的遍历) 例如: 给定一个二叉树 {1,#,2,3}, 1 \ 2 / 3 返回的层次遍历的结果是: [ [3], [9,20], [15,7] ] ++++++++++++++++++++++++++++++++++++++++++++++++++++…

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? 代码: stack 1: /** * Definition for a bin…

题目: Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its bottom-up level orde…

就把vector改成用栈类存放层次遍历的一层的序列 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 给定一个二叉树,自底向上的返回他的层次遍历的节点的values.(提示,从左到右,一层一层的遍历,但是这里是从叶子节点到根节点) 例如: 给定一个二叉树 {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 返回的层次遍历的结果是: [ [15,7] [9,…

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Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its bottom-up level order tr…

Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its level order traversal as: [ [3], [9,20], [15,7] ] 分层…

Binary Tree Level Order Traversal II Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15…