Implement a rate limiter
shouldAllowRequest() that returns true if the incoming requests have arrived at a rate less than or equal to specified rate, […]
Data Structures
Bit Manipulation, String Manipulation
Boolean String Value
Given a string consisting of only 0, 1, A, B, C where A = AND B = OR C =
Algorithms, Math Problems, String Manipulation
Print String Permutations
How will you print all permutations of characters in a string? 2026 Update: String Permutations — Three Approaches and the
Algorithms, Dynamic Programming, String Manipulation
Longest palindrome in a string
Write a function to find the longest palindrome in a string. 2026 Update: Longest Palindrome — Character Frequency Approach There
Dynamic Programming, Math Problems
Prime number problem
You need to a number of floors in a building. There are 68 floors (numbered 1 to 64). Conditions: 1.
Data Structures, System Design
Missing country code
Missing Country Code Imagine you get a data set from a client that contains addresses from 150 countries all around
Math Problems
Prime number problem
A man has to buy 7 floors in a building. Numbered floor 1 to 68. Conditions: 1. He cannot buy
Logic Puzzles
100 doors to be painted
You have 100 doors to be painted and 2 painters. 1 starts at one end and paints every other door.
Coding Interview Questions
5 Unbreakable Light Bulbs and a 80 Floor Building
IF You have 5 unbreakable light bulbs and a 80 floor building. Using fewest possible drops, determine how much of
Amazon Interview Questions, Arrays
Amazon Interview Question: Count Negative Integers in Matrix
2026 Update: Sorted Matrix Search — From O(mn) to O(m+n) If the matrix is sorted (rows and columns both non-decreasing),
Coding Interview Questions
Implement a Function to Return a Ratio
Implement a function to return a ratio from a double function (0.25 -> 1/4). If the function tolerance is .01
Logic Puzzles
Three People on a Weak Bridge
Three people need to cross a weak bridge at night. They have just one turn and the bridge is only
System Design
Server to Process Fair Number of Functions
How would you design a server that has to process a fair number of functions of a requests in a
Coding Interview Questions
Function that Multiples 2 Integers
Write a multiply function that multiples 2 integers without using “*”. 2026 Update: Integer Multiplication — Without Using Multiply Operator
Data Structures
Find Out if a Linked List has a Cycle
Without marking nodes, find out if a linked list has a cycle in it or not. 2026 Update: Floyd’s Cycle