Algorithms

1 · A + B Problem
8 · Rotate Character Array
14 · First Position of Target
56 · Two Sum
60 · Search Insert Position
82 · Single Number
147 · Narcissistic Number
765 · Valid Triangle
1053 · Largest Number At Least Twice of Others
1082 · Employee Importance
1314 · Power of Two

Database

1913 · Query Student Enrollment Information
1918 · The height of the second tallest player
1919 · Members Whose Scores Exceed the Group leader
1920 · Find a Classmate with the Same Name
1921 · Players Who Never Recharge
1922 · Delete Duplicate Names
1923 · Increasing Number of Infections
1924 · Recommend Student to Study Science
1925 · At Least Three Players Have Scored
1926 · Popular Hero
1927 · Coin Flip
1928 · Analysis of Online Class I
1929 · Analysis of Online Class II
1930 · Public Rental Housing Information Query
1931 · Find Specific Patient
1932 · Students with the Most Failed Subjects I
1933 · Students with the Most Failed Subjects II
1934 · Zhang San's Story I
1935 · Zhang San's Story II
1936 · Zhang San's Story III
1937 · Consecutive Empty Boxes
1938 · Query User Email
1939 · Resume Delivery I
1940 · Resume Delivery II
1941 · Find Right Triangle
1942 · Two Nearest Saplings
1943 · Looking for Students of a Certain Height
1944 · Bike Sharing
1945 · Club Annual Competition Score Ranking I
1946 · Club Annual Competition Score Ranking II
1950 · Query courses with more than 800 students
1951 · Query courses with given teacher
1952 · Query teachers over 20 years old
1953 · Query the name of the Chinese teacher
1954 · Query course information with the number of students within a specified range
1955 · Query teachers who do not meet the conditions
1956 · Query information about Eastern Heretic teachers
1957 · Inquire about courses starting before May 2020
1958 · Query the courses that meet the conditions taught by the specified teacher
1959 · Query information about Chinese and British teachers
1960 · Query course information for a specific time
1961 · Query information about non-Japanese and non-American teachers
1962 · Query courses with teacher id other than 1 and 3
1963 · Search for teachers aged 20~25 whose nationality is not Chinese or British
1964 · Query for course information about the number of students within the specified range
1965 · Search for information on teachers who are not within the age range of 20 to 30 years
1966 · Use NOT BETWEEN to search for teachers with Chinese nationality
1967 · Search for courses starting with the letters 'D' to 'O'
1968 · Query the course name with the first two letters between 'Db' and 'Dy'
1969 · Query the courses starting in 2020
1970 · Search for courses with a creation date of June to August 2020
1971 · Search for teachers whose email is empty
1972 · Inquire about Chinese and Japanese teachers who have e-mail addresses
1973 · Search for all courses starting with the letter 'D'
1974 · Query teacher information by email
1975 · Inquire about the teacher who is Tencent's mailbox and is of Chinese nationality
1976 · Sort course information by number of students
1977 · Sorted by age of Chinese teachers in descending order
1978 · Sort by age of Chinese teachers in ascending order
1979 · Check the three courses with the lowest number of students
1980 · Search for the oldest Chinese teacher
1981 · Check the nationality of all teachers
1982 · Check the age of teachers and sort them in ascending order
1983 · Query the average number of students in the curriculum
1984 · Count the number of different teacher_id
1985 · Number of teachers aged 20 to 28 who are Chinese and British nationals
1986 · Query the maximum number of students in all courses
1987 · Find the age of the oldest Chinese teacher
1988 · Check the number of students in the course with the lowest number of students
1989 · Check the age of the youngest teacher
1990 · The total number of students enroll in all courses
1991 · Count the total number of students for teacher #3
1992 · Check average course enrollment
1993 · Delete the course called Dynamic Programming
1994 · Update all course information
1995 · Check the average age of teachers over 20 years old
1996 · Determining whether a teacher has a mailbox
1997 · Check the information of teachers who do not have email and are older than 20 years old
1998 · Statistics for courses in January to May 2020
1999 · Query the number of students and the course information that meets the requirements of the course name
2000 · Search for course information of System Design
2001 · Query the course information of 'Web' or 'Big Data'
2004 · Delete all courses until 2020
2005 · Query information about 18-year-old Chinese teachers
2006 · Query all courses
2007 · Check course name and class size
2008 · Query the course information of two courses
2009 · Query all teachers
2010 · Search all course names
2011 · Search for information on courses with more than 1000 participants 2012 · Find course information for the course named Artificial Intelligence
2013 · Check the name of the teacher
2014 · Query course name and course creation time
2015 · Inserting Python course information into the course table
2016 · Update the email address of the designated teacher
2017 · Inserting SQL course information into the course table
2018 · Insert Flash Sale course information into the specified column of the course schedule
2019 · Delete all rows in the table
2020 · Update on the number of students choosing artificial intelligence
2021 · Insert teacher information into the specified column of the teachers table
2022 · Delayed all course creation dates by one year
2023 · Calculate the number of days from 01/13/2018 to the time of course creation
2024 · Query the course name and year of creation date of all course schedules
2025 · Check the course creation time in the course schedule
2026 · Insert the current time into the table (accurate to milliseconds)
2027 · Query course creation date by 'year month'
2028 · Postpone all course creation dates by one day
2029 · Calculate the number of days from 03/26/2019 to the course creation time
2030 · Query the hours of all course creation times
2031 · Advance all course creation dates by one month
2032 · Advance all course creation dates by one day
2033 · Query the course name and creation time in seconds for all course schedules
2034 · Check the average age of teachers at the end of the specified mailbox
2035 · Calculate the number of years difference between the start date and the current date of all courses in the course schedule
2036 · Calculate the number of months difference between the given date and the creation date of all courses in the course schedule
2037 · Search for course titles and course dates through August 2020
2038 · Search for the date and time in the course creation time of the course schedule respectively
2039 · Query the creation date of the course in the course schedule
2040 · Search for courses with an instructor id of less than 3 and more than 800 students
2041 · Search for information on courses taught by designated teachers
2042 · Query all course names in the course schedule and the year and month of the creation date
2043 · Search for courses created in the first quarter
2044 · Output Hello SQL
2045 · Output Hello LintCode
2046 · The date the course was created is displayed in 'year-month-day hour:minute:second'
2047 · Copy all the data in the teacher table to another table
2048 · Search for information on all courses taught by a given teacher
2049 · Change the course name created by the teacher Western Venom
2050 · Search for teacher‘s name and the name of courses they taught
2051 · Search for the names of teachers from China and the names of courses they taught
2052 · Check the name of the instructor, email address and the name of courses they taught
2053 · Check the name, email and course name of the teacher from China
2054 · Check the course name and the age of the corresponding instructor
2055 · Search for all course names and their corresponding instructor names and nationalities
2056 · Copy the data in the teachers table that are older than 20 to another table
2057 · Modify course information created by instructor Eastern Heretic
2058 · Delete all courses for teachers younger than 21 years old
2059 · Remove faculty who have created courses before 2020
2060 · Search for the name of the teacher for the 'Big Data' course
2061 · Check the course title and email address of the instructor
2062 · Query the id and name of all courses taught by the specified teacher
2063 · Search for the names of all courses taught by teachers whose nationality is 'USA'
2064 · Check course information for courses with more students than Western Venom teachers
2065 · Check the course names of all courses taught by all teachers who are older than 20 years old
2066 · Search for course information for courses with more students than the number of students in all courses of the oldest teacher
2067 · Search for information on any course with more students than the 'Eastern Heretic' class size
2068 · Check the maximum age of teachers of different nationalities
2069 · Search for the course name and number of students in the course with the highest number of students per instructor
2070 · Search for the name of a course created later than the creation time of any of the specified teacher's courses
2071 · Search for information on the oldest faculty member whose nationality is American
2072 · Search for course names of all courses taught by teachers who are not older than 20 years old
2073 · Query the id and and the number of students for all courses taught by teachers whose nationality is not 'USA' and 'UK'

2074 · Search for the names of teachers whose average number of students in classes taught by all teachers exceeds the average number of students in all courses
2075 · Check the number of teachers in different countries
2076 · Search for teacher information based on national average age
2077 · Search for information on courses and instructors with the highest number of students
2078 · Find out the number of teachers of different ages
2079 · Count the total number of students in each teacher's course
2080 · Search for the name of the instructor and the total number of students in all the instructor's courses with less than 3000 students
2081 · Insert the current date into the table
2082 · Statistics on the number of courses taught by each teacher
2084 · Add primary key constraints to the course table courses
2085 · Remove the primary key constraint from the course table courses
2086 · Search for the nationality of the teacher starting with 'U' and the total number of students between 2000 and 5000 and the total number of students of that nationality
2091 · Adding Foreign Key Constraints to Course Tables
2092 · Search for a lecturer number
2093 · Check the portfolio of courses and teachers
2136 · Find out when a course was created and the nationality of the teacher
2459 · Nth highest player height
2460 · Player Height Ranking1
2499 · Height of players appearing consecutively
2500 · Highest scoring player in the team
2542 · Update Linghu Chong's email
2544 · Insert information about Feng Qingyang
2547 · Query all information in the teachers table
2548 · Update Southern Emperor's email
2553 · Delete Linghu Chong's message
2554 · Insert information about Chong Xu
2556 · Update the age of Linghu Chong
2557 · Insert information about Xie Xun
2559 · Withdrawal of age update for Linghu Chong
2560 · Undo the insertion of Xie Xun's message
2564 · Create a Trigger "before_teachers_insert"
2565 · Create a Trigger "before_teachers_update"
2567 · Delete the Trigger "before_teachers_insert"
2568 · Delete the Trigger "before_teachers_update"
2569 · Normative courses table data insert
2570 · New data processing of recruitment information statistics table
2572 · New data trigger message alert
2573 · Backup New Data Trigger
2575 · Normative courses table data update
2576 · Update data processing of recruitment information statistics table
2577 · Backup Update Data Trigger
2578 · Update data trigger message alert
2581 · Automatic backup when deleting teacher information
2583 · Delete data trigger message alert
2587 · Associated processing when deleting teachers table information (I)
2592 · Associated processing when deleting teachers table information (II)
2598 · Show all triggers for teachers table
2616 · Insert Kansas information into the teacher table
2617 · View the current transaction isolation level of the database
2620 · View the self-incrementing locking pattern for MySQL databases
2627 · Troubleshoot the current database table locks and view the table lock analysis
2633 · Troubleshoot the current database row locks and view row lock analysis
2635 · The use of optimistic locks and pessimistic locks (I)
2654 · Put a line lock on the data 'id = 3'
2664 · Recognizing SQL Views (I)
2665 · Recognizing SQL Views (II)
2674 · Creating a simple SQL View (I)
2676 · Creating a simple SQL View (II)
2683 · Zhang San's MySQL Learning Path (I)
2685 · Zhang San's MySQL Learning Path (II)
2689 · Redefining the teachers view
2692 · Count the total number of students taught by each faculty member
2700 · Update Linghu Chong's age by view
2702 · Delete Linghu Chong's teacher data by view
2704 · Zhang San's MySQL Learning Path (III)
2705 · Show view in the current database
2706 · Renaming views (I)
2707 · Renaming views (II)
2708 · Drop View (I)
2709 · Drop View (II)
2715 · View Processing Algorithm Merge
2716 · View Processing Algorithm TEMPTABLE
2720 · Creating a view that ensures consistency (I)
2721 · Creating a view that ensures consistency (II)
2723 · Showing the definition of a view
2724 · Cascade checking of views
2725 · Local checking of views
2760 · Understanding SQL Procedures (I)
2761 · Understanding SQL Procedures (II)
2799 · Creating a procedure for inserting data in bulk
2800 · Zhang San's MySQL Learning Path (IV)
2801 · Delete Stored Procedure (I)
2802 · Delete Stored Procedure (II)
2806 · MySQL Stored Procedure IN Parameters I
2807 · MySQL Stored Procedure IN Parameters II
2808 · MySQL Stored Procedure OUT Parameters I
2809 · MySQL Stored Procedure OUT Parameters II
2810 · MySQL Stored Procedure INOUT Parameters I
2811 · MySQL Stored Procedure INOUT Parameters II
2812 · MySQL Stored Procedure Variables I

Python

2089 · Implement timer decorator
2097 · Find the sum of two parameters
2098 · Read the values in the file and sum them
2105 · Write Hello World! in the file
2106 · Create a file directory and write Hello World!
2107 · Copy files in bulk
2123 · Get yesterday's date
2124 · print hello
2125 · Call the methods in the file main
2126 · Import one of the files in a module folder
2127 · Implementing reverse sorting of numbers in a list
2128 · Use of list built-in methods
2129 · Modify the value of a specified subscript of a list
2137 · Print out SMS verification code
2140 · The number of the two numbers in the list whose sum is equal to n
2142 · Replace the elements in a string
2143 · Implementing a shopping cart program
2146 · Implement Decorator with Parameters
2178 · Iterators and Fibonacci series
2199 · Remove empty lines from files
2207 · Filter out all odd numbers
2211 · Judge the number of palindrome
2240 · Update string
2252 · Judgment Results
2257 · Determining whether a number is prime or not
2258 · Find the largest prime number backwards
2261 · Delete elements in the list
2264 · Convert upper and lower case letters in a string
2273 · Sequential Output (Python version)
2276 · Modify and delete elements in the dictionary
2960 · Define a function
2324 · Output String In Reverse Order (Python version)

Java

2088 · First Java Code: Print Hello World
2157 · Print Welcome to LintCode!
2159 · Printing strings by splicing
2400 · Create a HashMap set and add data
2848 · Refining the right class

Git

2540 · Your First Git Commit
2613 · Submit a document amendment
2619 · Track and submit document changes
2626 · Add files to the stage
2660 · git Branch Renaming
2668 · Create and switch branches
2669 · Modify the last commit
2671 · Backtrack and recommit commit
2696 · Cache and restore across branches
2701 · Remove documents
2711 · Move documents
2732 · View submission history
2741 · Tagging
2746 · Formatted view of historical submission records

Linux Command

2513 · Remove Folder
2514 · Copy folder
2574 · Copying documents
2582 · Moving documents
2585 · Moving folders
2586 · Delete document
2593 · Show current directory
2594 · Access to the specified directory
2597 · List file directories and file names
2599 · Compare the differences between the two documents
2603 · Checking disk usage
2604 · View the space occupied by a file
2605 · View username and group name
2606 · View user ID and group ID
2608 · Compare the two documents
2623 · Find eligible files in a directory (i)
2628 · Find eligible files in a directory (ii)
2630 · Find eligible files in a directory (iIi)
2632 · Intercept the string at the specified position
2643 · Create file link (I)
2645 · Viewing the contents of a file using a different binary
2648 · View file contents using different decoding methods
2653 · Display String (i)
2656 · Create file link (II)
2679 · Display String (ii)
2681 · Display String (iii)
2691 · View file details
2693 · File creation preset permissions
2695 · Retrieves the specified items of a document by different delimiters
2697 · Find a compliant document (i)
2698 · Find a compliant document (ii)
2710 · Copy Files (i)
2712 · View the type of command
2713 · Find the location of the command
2719 · Execute expression
2726 · File View
2727 · Compare document differences by column (ii)
2729 · Writing to a file
2730 · Delete file contents
2736 · Document content sorting(i)
2737 · Document content sorting(ii)
2740 · Expression evaluation (I)
2743 · Expression evaluation (III)
2752 · Word counts
2754 · Set command aliases
2755 · Display System Information
2757 · Setting up the shell

OOP

204 · Singleton
218 · Student Level
222 · Setter and Getter
454 · RectangleArea
455 · Student ID
456 · Reference
496 · Toy Factory
712 · Vending machine OO Design

Concurrency

2090 · Print Zero, Even and Odd Number II
2416 · N threads to achieve quick sort
2439 · Start 2 threads to print "Hello" and "World" respectively
2449 · Sleep Sort
2450 · Start the thread to print hello world