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…

对于一般的二叉树,统计节点数目遍历一遍就可以了,但是这样时间复杂度O(n),一下就被卡住了. 这题首先要明白的是,我们只需要知道叶子节点的数目就能统计出总节点树. 想法1: 既然是完全二叉树,我肯定是从左子树开始看,如果左子树不完整,右子树就不用再遍历了.由此形成一个递归的搜索过程,先搜索左子树,如果不完整,直接停止搜索,统计完毕:否则,还要再搜索右子树. 这样就能避开完全搜索遍历整棵树,但是当树接近满树的时候实际上还是将整颗树遍历了一遍. 想法2: 完全二叉树不同于满树的一点是,我们只能肯定它…

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…

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…

[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…

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 last level are as far left…

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…