CoolMind

If you cannot measure it, you cannot improve it.

Sliding maximum of range k subarray

Problem Solution Complexity analysis Problem This problem was asked by Google. Given an array of integers and a number k...

Posted by chunyang on July 15, 2020

Longest file path size

Problem Solution Problem This problem was asked by Google. Suppose we represent our file system by a string in the following manner: The ...

Posted by chunyang on July 15, 2020

Fixed size queue

Problem Solution Problem This problem was asked by Twitter. You run an e-commerce website and want to record the last N order ids in a log...

Posted by chunyang on July 13, 2020

Pick a number randomly from an unlimited stream

Problem Solution Comments Problem This problem was asked by Facebook. Given a stream of elements too large to store in memory, pick a ra...

Posted by chunyang on July 12, 2020

Estimate PI

Problem Solution Problem This problem was asked by Google. The area of a circle is defined as $\pi r^{2}$ . Estimate $\pi$ to 3 decimal pl...

Posted by chunyang on July 11, 2020

At most distinct K

Problem Solution Problem This problem was asked by Amazon. Given an integer k and a string s, find the length of the longest substring tha...

Posted by chunyang on July 10, 2020

Climb up staircase

Problem Solution Reference Problem This problem was asked by Amazon. There exists a staircase with N steps, and you can climb up either ...

Posted by chunyang on July 9, 2020

An autocomplete system

Problem Solution Comments Problem This problem was asked by Twitter. Implement an autocomplete system. That is, given a query string s a...

Posted by chunyang on July 8, 2020