Longest Absolute Path in File System Representation
Find the length of the longest absolute path to a file within the abstracted file system. The length is measured in characters.
Efficient Order Log Storage
You manage an e-commerce website and need to keep track of the last N order IDs in a log. Design a data structure that supports the following operations efficiently:
February 6, 2025 | Data Structure, dsa, Twitter | No comments
Select a Random Element from a Stream
You are given a stream of elements that is too large to fit into memory. Write an algorithm to select a random element from the stream with equal probability
Estimate π Using Monte Carlo Method
The formula for the area of a circle is given by πr². Use the Monte Carlo method to approximate the value of π to three decimal places.
Longest Substring with K Distinct Characters
Given an integer k and a string s, write a function to determine the length of the longest substring in s that contains at most k distinct characters.
Staircase Climbing Ways
There is a staircase with N steps, and you can ascend either 1 step or 2 steps at a time. Write a function to calculate the number of unique ways to climb the staircase. The sequence of steps matters.
January 11, 2025 | Amazon, Data Structure, dsa | No comments
Job Scheduler Implementation
Design a job scheduler that accepts a function f and an integer n. The scheduler should execute the function f after a delay of n milliseconds.
Largest Sum of Non-Adjacent Numbers
Problem Statement (Asked By Airbnb) Given a list of integers, write a function to compute the largest sum of numbers such that no two numbers are adjacent in the list. The input may contain zero or negative values. For example, [2, 4, 6, 2, 5] should return 13, since we pick 2, 6, and 5. [5, 1, 1, 5] should return 10, since we […]
Count Unival Subtrees in a Binary Tree
A unival tree (short for “universal value tree”) is a tree in which all nodes have the same value.
Given the root of a binary tree, determine how many unival subtrees it contains.
For example, the following tree has 5 unival subtrees:
January 6, 2025 | Binary Tree, dsa, DSA Sheet, Google | No comments
Count Decoding Ways for Encoded Messages
Problem Statement (Asked By Facebook) Given the mapping a = 1, b = 2, …, z = 26, and an encoded message, count the number of possible ways to decode it. For example, the message ‘111’ would give 3, since it could be decoded as ‘aaa’, ‘ka’, and ‘ak’. You can assume that the messages […]
January 5, 2025 | DP, dsa, DSA Sheet, Facebook | No comments