I was asked to solve this problem in a interview:
Suppose there are 4 million comments each with its own id and timestamp. Design an efficient algorithm that finds the most recent 1000 comments. You have 40 servers, and each server can handle 10 thousand comments at a time.
I was thinking about using MapReduce. How do i implement map and reduce function in order to to solve this problem?
Processing big data on distributed system
53 views Asked by Yichuan Wang At
1
There are 1 answers
Related Questions in HADOOP
- Angular Show All When No Filter Is Supplied
- Why does a function show up as not defined
- I count the time the user takes to solve my quiz using Javascript but I want the same time displayed on another page
- Set "More" "Less" font size
- Using pagination on a table in AngularJS
- How to sort these using Javascript or Jquery Most effectively
- how to fill out the table with next values in array with one button
- State with different subviews
- Ajax jQuery firing multiple time display event for the same result
- Getting and passing MVC Model data to AngularJS controller
Related Questions in MAPREDUCE
- Angular Show All When No Filter Is Supplied
- Why does a function show up as not defined
- I count the time the user takes to solve my quiz using Javascript but I want the same time displayed on another page
- Set "More" "Less" font size
- Using pagination on a table in AngularJS
- How to sort these using Javascript or Jquery Most effectively
- how to fill out the table with next values in array with one button
- State with different subviews
- Ajax jQuery firing multiple time display event for the same result
- Getting and passing MVC Model data to AngularJS controller
Related Questions in BIGDATA
- Angular Show All When No Filter Is Supplied
- Why does a function show up as not defined
- I count the time the user takes to solve my quiz using Javascript but I want the same time displayed on another page
- Set "More" "Less" font size
- Using pagination on a table in AngularJS
- How to sort these using Javascript or Jquery Most effectively
- how to fill out the table with next values in array with one button
- State with different subviews
- Ajax jQuery firing multiple time display event for the same result
- Getting and passing MVC Model data to AngularJS controller
Related Questions in GFS
- Angular Show All When No Filter Is Supplied
- Why does a function show up as not defined
- I count the time the user takes to solve my quiz using Javascript but I want the same time displayed on another page
- Set "More" "Less" font size
- Using pagination on a table in AngularJS
- How to sort these using Javascript or Jquery Most effectively
- how to fill out the table with next values in array with one button
- State with different subviews
- Ajax jQuery firing multiple time display event for the same result
- Getting and passing MVC Model data to AngularJS controller
Popular Questions
- How do I undo the most recent local commits in Git?
- How can I remove a specific item from an array in JavaScript?
- How do I delete a Git branch locally and remotely?
- Find all files containing a specific text (string) on Linux?
- How do I revert a Git repository to a previous commit?
- How do I create an HTML button that acts like a link?
- How do I check out a remote Git branch?
- How do I force "git pull" to overwrite local files?
- How do I list all files of a directory?
- How to check whether a string contains a substring in JavaScript?
- How do I redirect to another webpage?
- How can I iterate over rows in a Pandas DataFrame?
- How do I convert a String to an int in Java?
- Does Python have a string 'contains' substring method?
- How do I check if a string contains a specific word?
Popular Tags
Trending Questions
- UIImageView Frame Doesn't Reflect Constraints
- Is it possible to use adb commands to click on a view by finding its ID?
- How to create a new web character symbol recognizable by html/javascript?
- Why isn't my CSS3 animation smooth in Google Chrome (but very smooth on other browsers)?
- Heap Gives Page Fault
- Connect ffmpeg to Visual Studio 2008
- Both Object- and ValueAnimator jumps when Duration is set above API LvL 24
- How to avoid default initialization of objects in std::vector?
- second argument of the command line arguments in a format other than char** argv or char* argv[]
- How to improve efficiency of algorithm which generates next lexicographic permutation?
- Navigating to the another actvity app getting crash in android
- How to read the particular message format in android and store in sqlite database?
- Resetting inventory status after order is cancelled
- Efficiently compute powers of X in SSE/AVX
- Insert into an external database using ajax and php : POST 500 (Internal Server Error)
As the question specifically asks about efficient algorithms, I suspect the interviewer cares less about techniques like MapReduce but more the underlying algorithm you will use. This seems like an application of Merge Sort. In this case you would divide the work load into 10K chunks, assign each chunk for sorting on the nodes and merge. Once complete you should have all 4 million entries sorted by date, you can than take the most recent 1000 entries. This algorithm would run in O(n log n)