• 1. Rxswift creates observable sequences


    Empty() method initialization //An observable empty content is created let ob = Observable.empty() //First, write a simple subscription method ob.subscribe {print “} The just() method passes in the default value initialization //There is no need to give a generic, it will be automatically pushed out according to just let ob = Observable.just (initialization default) The […]

  • Insertion sort algorithm


    The insert sort pair divides the array into sorted and unsorted parts. Generally, the left side is sorted and the right side is unsortedThen the first element of the unsorted sequence is taken as the element to be inserted, and then the sorted sequence is traversed,Note that we have to traverse the sorted sequence from […]

  • Python learning notes: data type — number type


    Number type Numerical type, which is usually used to store values, is the most commonly used variable type;The numeric types in Python include the following types:Integer、Long integer、Boolean、Double-precision floating、Complex number。 IntegerPS novice note: many people in the process of learning Python will encounter a variety of vexed questions, no one answers easy to give up. For […]

  • Sql:SQL Server CREATE SEQUENCE statement


    —Auto growth jumps to 1001 https://stackoverflow.com/questions/17587094/identity-column-value-suddenly-jumps-to-1001-in-sql-server –1. Use sequence https://docs.microsoft.com/zh-cn/sql/t-sql/statements/create-sequence-transact-sql?view=sql-server-ver15 –2. Register the startup parameter – t272 for SQL server IF EXISTS(SELECT * FROM sys.sequences WHERE name = N’Id_Sequence’) DROP SEQUENCE Id_Sequence; GO CREATE SEQUENCE Id_Sequence AS INT Start with 1 — count from 1 Increment by 1 — how many at a time MinValue […]

  • Leetcode 99. Restore binary search tree | Python


    99. Restore binary search tree Source: leetcode https://leetcode-cn.com/problems/recover-binary-search-tree subject Two nodes in the binary search tree are wrongly exchanged. Please restore the tree without changing its structure. Example 1: Input: [1,3, null, null, 2] 1 / 3 \ 2 Output: [3,1, null, null, 2] 3 / 1 \ 2 Example 2: Input: [3,1,4, null, null, […]

  • Print binary tree from top to bottom


    Python is short and sharp, and golang is simple and efficient Question surface Each node of the binary tree is printed from top to bottom, and the nodes of the same layer are printed from left to right.Given binary tree[3,9,20,null,null,15,7], 3 / \ 9 20 / \ 15 7 return [3,9,20,15,7] python Queue in and […]

  • Leetcode 546. Remove box | Python


    546. Remove the box subject Some boxes with different colors are given. The colors of boxes are represented by numbers, that is, different numbers represent different colors.You will go through several rounds to remove the boxes until all the boxes are removed. Each round you can remove consecutive K boxes with the same color (k […]

  • Time series prediction using Microsoft power Bi


    AuthorCompile | VKSource | analytics vidhya introduce Time series forecasting is a very important area of machine learning because it allows you to “foresee” ahead of time and plan your business accordingly. In this blog, we will learn what time series forecasting is, how power Bi makes time series prediction graphs and the modules that […]

  • Monte Carlo analysis of web page views


    By Michael GroganCompile | VKSource: toward Data Science Monte Carlo method has been widely used in finance and other fields to model various risk scenarios. However, this method also has important applications in other aspects of time series analysis. In this particular example, let’s look at how the Monte Carlo method can be used to […]

  • Oracle Foundation (6): sequence, view, index


    1、 Sequence Sequence is a special object in Oracle database, which can generate continuous integer values. It can be used by multiple objects in the database, and is mainly used as the primary key value.1. Create sequenceStart value with:1Increment by: 1Maximum value: maxvalue:100Minimum value: minvalue:1Cycle | nocycleBuffer: cache 20 | nocache (default: 20)  create sequence s1;Note: […]

  • Leetcode – dynamic programming 1


    5. Longest palindrome string Given a string s, find the longest palindrome substring in S. You can assume that the maximum length of S is 1000. Example 1: Input: “babad”Output: “bab”Note: “ABA” is also a valid answer. Example 2: Input: “CBBD”Output: “BB” Train of thought 1The central extension means that each character is taken as […]

  • Week 15 of Arts | longest palindrome subsequence of leetcode | from Uber’s go programming specification


    ARTS Arts is an activity launched by Chen Hao in the geek time column. The aim is to keep learning through sharing. Each person writes arts once a week: algorithm is an algorithm problem, review is to read an English article, technique / tips is to share a small technology, share is to share a […]