LouisLan的学习简记 👋🏼

题目地址 https://leetcode.com/problems/minimum-depth-of-binary-tree/ 题目描述 Given a binary tree, find its minimum depth. The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node. Note: A leaf is a node with no children. Example: Given binary tree [3,9,20,null,null,15,7], 3 / \ 9 20 / \ 15 7 return its minimum depth = 2. 思路 二叉树的经典问题之最小深度问题就是就最短路径的节点个数，还是用深度优先搜索 DFS 来完成，万能的递归啊。首先判空，若当前结点不存在，直接返回 0。然后看若左子结点不存在，那么对右子结点调用递归函数，并加 1 返回。反之，若右子结点不存在，那么....

? ## ? 基于神经网络的降雨预测 占坑学习，以后再理解，脑壳痛！ 源数据：tianjin.xlsx python代码： import numpy as np import pandas as pd import sklearn filename = r'tianjin.xlsx' data = pd.read_excel(filename) pd.set_option('display.max_columns',None) # data.head() # data = data.drop('ET0',axis=1)#去除数据集中的ET0 data.head() # 读取前五行数据 len(data) len(data.columns) print(len(data.columns)) data = data.drop(['PMax','ET0', 'Rn', 'Wind', 'PMean', 'TMean', 'Delta','Gama'],axis = 1)#去除不需要的参数 print(data) #data = data.drop(['PMax', 'Wind', 'PMin....

题目地址 https://leetcode.com/problems/balanced-binary-tree/ 题目描述 Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as: a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Example 1: Given the following tree [3,9,20,null,null,15,7]: 3 / \ 9 20 / \ 15 7 Return true. Example 2: Given the following tree [1,2,2,3,3,null,null,4,4]: 1 / \ 2 2 / \ 3 3 / \ 4 4 Return false. 思路 求二叉树是否平衡，根据题目中的定....

题目地址 https://leetcode.com/problems/convert-sorted-list-to-binary-search-tree/ 题目描述 Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Example: Given the sorted linked list: [-10,-3,0,5,9], One possible answer is: [0,-3,9,-10,null,5], which represents the following height balanced BS....

题目地址 https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/ 题目描述 Given an array where elements are sorted in ascending order, convert it to a height balanced BST. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Example: Given the sorted array: [-10,-3,0,5,9], One possible answer is: [0,-3,9,-10,null,5], which represents the following height balanced BST: 0 / \ -3 9 / /....

题目地址 https://leetcode.com/problems/binary-tree-level-order-traversal-ii/ 题目描述 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 traversal as: [ [15,7], [9,20], [3] ] 思路 从底部层序遍历其实还是从顶部开始遍历，只不过最后存储的方式有所改变，可以参见我之前的博文 Binary Tree Level Order Traversal 关键点解析 代码 解法一： class Solution { public: vector<v....

题目地址 https://leetcode.com/problems/construct-binary-tree-from-inorder-and-postorder-traversal/ 题目描述 Given inorder and postorder traversal of a tree, construct the binary tree. Note: You may assume that duplicates do not exist in the tree. 思路 这道题要求从中序和后序遍历的结果来重建原二叉树，我们知道中序的遍历顺序是左-根-右，后序的顺序是左-右-根，对于这种树的重建一般都是采用递归来做，可参见我之前的一篇博客Convert Sorted Array to Binary Search Tree 将有序数组转为二叉搜索树。针对这道题，由于后序的顺序的最后一个肯定是根，所以原二叉树的根节点可以知道，题目中给了一个很关键的条件就是树中没有相同元素，有了这个条件我们就可以在中序遍历中也定位出根节点的位置，并以根节点的位置将中序遍历拆分为左右两个部分，分别对其递....

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dplayer 测试播放 嘀嘀嘀哒哒哒 老阿姨 注：视频源地址见：https://www.bilibili.com/video/BV1rs411u7K3 上面是分割线 注： 添加代码备注 const dp = new DPlayer({ container: document.getElementById('dplayer'), autoplay: false, theme: '#FADFA3', loop: true, lang: 'zh-cn', screenshot: true, hotkey: true, preload: 'auto', logo: 'logo.png', volume: 0.7, mutex: true, video: { url: 'dplayer.mp4', pic: 'dplayer.png', thumbnails: 'thumbnails.jpg', type: 'auto', }, subtitle: { url: 'dplayer.vtt', type: 'webvtt', fontSize: '25px', bottom: '10....

定制皮肤 前景提示：本人是个纯后端接口开发(java)，对于前端涉略较浅，这篇文章的目的是为了方便那些同道中人或者前端小白能够基于现有的solo皮肤简单开(bai)发(piao)出一套适合自己的博客样式，其间若有冒犯，欢迎来犯，一起进步！