6. Design a Hit Counter/Webpage Visits Counter - Multi-Threaded
Write code for low level design of a webpage visits counter.
There are n webpages in a website numbered 0 to n-1.
Hundreds of users visit webpages of this website simultaneously.
You have to record visit count for each page and return them when required.
Note :
- For Java, code will be tested in a MULTI-THREADED environment, so use thread safe data structures and handle synchronization properly.
- For Python, code will be tested in a single threaded environment
- There will be at max 1000 webpages
Your solution should implement below methods :
Method : init(int totalPages, Helper06 helper)
- totalPages is the 'n' we discussed above i.e. total number of webpages in the website.
- Use this method to initialize your instance variables
- use helper's methods for printing logs else logs will not be visible.
Method : incrementVisitCount(int pageIndex)
- increment visit count for webpage at pageIndex by 1.
Method : getVisitCount(int pageIndex)
- return total visit count for a given page
For the same pageIndex, incrementVisitCount() and getVisitCount() will never be called concurrently.
This is done to maintain correctness and eventual consistency in the system.
Example :
init(totalPages = 2, helper = helper)
incrementVisitCount(pageIndex = 0)
incrementVisitCount(pageIndex = 1)
incrementVisitCount(pageIndex = 1)
incrementVisitCount(pageIndex = 1)
incrementVisitCount(pageIndex = 0)
getVisitCount(pageIndex = 0) : returns 2
getVisitCount(pageIndex = 1) : returns 3
There are n webpages in a website numbered 0 to n-1.
Hundreds of users visit webpages of this website simultaneously.
You have to record visit count for each page and return them when required.
Note :
- For Java, code will be tested in a MULTI-THREADED environment, so use thread safe data structures and handle synchronization properly.
- For Python, code will be tested in a single threaded environment
- There will be at max 1000 webpages
Your solution should implement below methods :
Method : init(int totalPages, Helper06 helper)
- totalPages is the 'n' we discussed above i.e. total number of webpages in the website.
- Use this method to initialize your instance variables
- use helper's methods for printing logs else logs will not be visible.
Method : incrementVisitCount(int pageIndex)
- increment visit count for webpage at pageIndex by 1.
Method : getVisitCount(int pageIndex)
- return total visit count for a given page
For the same pageIndex, incrementVisitCount() and getVisitCount() will never be called concurrently.
This is done to maintain correctness and eventual consistency in the system.
Example :
init(totalPages = 2, helper = helper)
incrementVisitCount(pageIndex = 0)
incrementVisitCount(pageIndex = 1)
incrementVisitCount(pageIndex = 1)
incrementVisitCount(pageIndex = 1)
incrementVisitCount(pageIndex = 0)
getVisitCount(pageIndex = 0) : returns 2
getVisitCount(pageIndex = 1) : returns 3
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It will train you to cover overall low level design of this question within 45-60 minutes of interview round.
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- Asks counter questions on your choice of design patterns, class structure etc.
- Gives pinpointed strengths and gaps final report on how you performed.
- Follows standard MAANG interview format for Low Level Design
- Will teach you which core functionalities to discuss during interview while leaving the rest.
- Asks counter questions on your choice of design patterns, class structure etc.
- Gives pinpointed strengths and gaps final report on how you performed.
- Follows standard MAANG interview format for Low Level Design