Spotify Interview Guide

Find the median of all sliding windows of a given size within an array of numbers. The window slides one position at a time from left to right.

Design a data structure to calculate the moving average of a stream of numbers. The moving average is calculated over a sliding window of a specified size.

You're given user website visit logs. Find the most frequent sequence of three websites visited by any user.

Find the length of the longest substring within a given string that contains no repeating characters. The substring must be contiguous.

Find two numbers in a given array that add up to a specific target value, and return their indices. Essentially, you need to efficiently locate the pair that satisfies the sum requirement.

Determine if a string containing parentheses is valid. A valid string has matching and properly nested opening and closing parentheses.

Find the kth largest element in an unsorted array. Note that it is the kth largest element in sorted order, not the kth distinct element.

Determine if a given string is a palindrome, considering only alphanumeric characters and ignoring cases. Essentially, check if the string reads the same forwards and backward after removing non-alphanumeric characters and converting to lowercase.

Determine if you can construct a ransom note from the letters in a magazine. Each letter in the magazine can only be used once.

Find the maximum depth (number of nodes along the longest path) from the root to a leaf node in a given binary tree. Essentially, you need to determine how 'tall' the tree is.

Imagine a grid representing rooms, some empty, some with walls, and some with gates. Fill each empty room with the distance to its nearest gate.

Calculate the nth Fibonacci number. The Fibonacci sequence starts with 0 and 1, and each subsequent number is the sum of the previous two.