Hen
2 min read If a hen and a half lay an egg and a half in a day and a half, how many […] Read article
Dynamic Programming
Arrays
Box ‘o Numbers
2 min read Arrange the numbers 1 to 8 in the grid below such that adjacent numbers are not in adjacent boxes (horizontally, Read article
Brain Teasers, Logic Puzzles
Coin Problem
2 min read some of you may have easily solved the pill weighing problem posed here. If so, you are going to love Read article
Coding Interview Questions
Parallel Lines
2 min read Solution Not really much to solve 🙂 2026 Update: Parallel Lines — Geometry Algorithms and Line Intersection Determining if lines Read article
Coding Interview Questions
Moving Circles
2 min read Solution You may be able to find the solution on the discussion forum. 2026 Update: Collision Detection — Computational Geometry Read article
Coding Interview Questions
Black Dots
2 min read Solution You may be able to find the solution on the discussion forum. 2026 Update: Gestalt Perception and Counting Algorithms Read article
Brain Teasers, Dynamic Programming
X Implies Y
3 min read Part I (you can’t use paper, you have to figure it out in your head) i have a black triangle, Read article
Bit Manipulation
XOR using NAND gates
2 min read Create an XOR gate using only NAND gates. (BTW, mostly all circuit problems assume you have two inputs plus 0 Read article
System Design
Smart Cookie
2 min read Did you ever wonder how they make those pillsbury cookie dough rolls with the intricate faces inside them? Look here and Read article
Data Structures
Wanna Play?
3 min read I offer to play a card game with you using a normal deck of 52 cards. the rules of the Read article
Math Problems
Crazy Guy on the Airplane
2 min read A line of 100 airline passengers is waiting to board a plane. they each hold a ticket to one of Read article
Coding Interview Questions
Chameleons
1 min read At one point, a remote island’s population of chameleons was divided as follows: 13 red chameleons 15 green chameleons 17 Read article
Brain Teasers, Logic Puzzles
Railroad Bridge
3 min read A man needs to go through a train tunnel. He starts through the tunnel and when he gets 1/4 the Read article
Math Problems
Cars on the Road
2 min read if the probability of observing a car in 20 minutes on a highway is 609/625, what is the probability of Read article
Algorithms, Logic Puzzles
Switches
3 min read The warden meets with 23 new prisoners when they arrive. He tells them, “You may meet today and plan a Read article
