Educative: Interactive Courses for Software Developers Level up your coding skills. No more passive learning. Interactive in-browser environments keep you engaged and test…www.educative.io This is an actual interview question asked at Uber and Oracle. Imagine you have a bucket that gets filled with tokens at the rate of 1 token per second. The bucket can hold a maximum of N tokens. Implement a thread-safe class that lets threads get a token when one…

Writing a Test Without Tools Write automated tests without any tools to learn how difficult the practice can be. Here is the function we want to test function isEmail(email) { const regex = new RegExp(/^[^@\s]+@[^@\s.]+\.[^@.\s]+$/); return regex.test(email); } We want to write the following tests: Return true when a valid email is passed into it …

In a lot of problems involving intervals, we either need to find overlapping intervals or merge intervals if they overlap. Given two intervals (‘a’ and ‘b’), there will be six different ways the two intervals can relate to each other: Merge Intervals Given a list of intervals, merge all the…

https://www.educative.io/courses/grokking-dynamic-programming-patterns-for-coding-interviews/RM1BDv71V60 0/1 Knapsack is based on the famous problem with the same name which is efficiently solved using Dynamic Programming. We will go through a set of problems to develop an understanding of DP. We will always start with a brute-force recursive solution to see to see the overlapping subproblems…

In problems where we deal with sorted array and need to find a set of elements that fulfill certain constraints, the Two Pointers approach becomes quite useful. The set of elements could be a pair, a triplet or even a subarray. Remove Duplicates From Sorted Array Given an array of…

Topological Sort of a directed graph is a linear ordering of its vertices such that for every directed edge (U, V) from vertex U to vertex v , U comes before V in the ordering. Given a directed graph, find the topological ordering of its vertices. Input: Vertices=4, Edges=[3, 2]…

The Fast & Slow pointer approach is a pointer algorithm that uses two pointers which move through the array at different speeds. This approach is quite useful when dealing with cyclic LinkedLists or arrays. By moving at different speeds, the algorithm proves that the two pointers are bound to meet…