CoolMind

If you cannot measure it, you cannot improve it.

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

Job scheduler

Problem Solution Reference Problem This problem was asked by Apple. Implement a job scheduler which takes in a function f and an integer...

Posted by chunyang on July 7, 2020

Maximum non-adjacent sum

Problem Solution Problem This problem was asked by Airbnb. Given a list of integers, write a function that returns the largest sum of non-...

Posted by chunyang on July 6, 2020

Xor linked list

Problem Solution Comments Problem This problem was asked by Google. An XOR linked list is a more memory efficient doubly linked list. In...

Posted by chunyang on July 5, 2020

Universal tree

Problem Solution Problem This problem was asked by Google. A unival tree (which stands for “universal value”) is a tree where all nodes un...

Posted by chunyang on July 5, 2020

Decode ways

Problem Solution Problem This problem was asked by Facebook. Given the mapping a = 1, b = 2, … z = 26, and an encoded message, count the n...

Posted by chunyang on July 5, 2020

Cdr and car of a pair

I have subscribed to a website. Every day an email will be sent to my email about the description of the problem. Problem Solution Problem ...

Posted by chunyang on July 1, 2020