完全二叉树的定义:若设二叉树的深度为h,除第 h 层外,其它各层 (1-h-1) 的结点数都达到最大个数,第 h 层所有的结点都连续集中在最左边,这就是完全二叉树. 解题思路:将树按照层进行遍历,如果出现null后还出现非null则能证明这个不是完全二叉树 https://leetcode.com/problems/check-completeness-of-a-binary-tree/discuss/205768/Java-easy-Level-Order-Traversal-one-whil…

2018-09-25 16:36:25 问题描述: 问题求解: 单纯遍历了一遍,emmm,果然TLE. 解题思路就是比较左边树高度和右边树高度,如果相等,那么就是一个满二叉树,返回1 << h - 1即可,如果不是,则递归的计算左右子树的个数. 时间复杂度:O(logn * logn) public int countNodes(TreeNode root) { if (root == null) return 0; int l = leftHeight(root); int r = righ…

1 题目 Given a complete binary tree, count the number of nodes. In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as possible. It can have between 1 and 2h nodes inclu…

[LeetCode]222. Count Complete Tree Nodes 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.me/ 题目地址:https://leetcode.com/problems/count-complete-tree-nodes/description/ 题目描述: Given a complete binary tree, count the n…

Count Complete Tree Nodes Given a complete binary tree, count the number of nodes. Note: Definition of a complete binary tree from Wikipedia: In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the…

原题链接在这里:https://leetcode.com/problems/count-complete-tree-nodes/ Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is complete…

题目: 求完全二叉树节点数. 思路: 满二叉树的节点数是2^k-1,k是树的深度. 所以我们可以先判断该树是否为满二叉树,然后是的话直接返回结果,如果不是递归地求解子树. 这样不用遍历所有的节点.复杂度小于O(N),比对所有点遍历复杂度要小,最好的情况是O(lgN). 推算大概在O(lgN)~O(N)之间. /** * Definition for a binary tree node. * function TreeNode(val) { * this.val = val; * this.le…

Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia: In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as po…

题目: Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely filled, and all nodes in the last level are as far left as…

Total Accepted: 32628 Total Submissions: 129569 Difficulty: Medium Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is comple…