Level 6: Interview classics
The famous trading-floor and quant-screen puzzles — strategy, encoding, optimal stopping, and game-theoretic backward induction.
36 problems
First 5 free · rest Premium
- 1→
100 Prisoners and 100 Boxes
●●●●●Expert~12 min
- 2→
Two Burning Ropes
●●●○○Medium~5 min
- 3→
Two Eggs, 100 Floors
●●●●○Hard~8 min
- 4→
1000 Bottles, One Poisoned
●●●●○Hard~7 min
- 5→
The Pirate Game
●●●●●Expert~10 min
- 6Premium
Dice Game with an Optional Re-roll
●●●○○Medium~5 min
- 7Premium
The Blue-Eyed Islanders
●●●●●Expert~12 min
- 8Premium
Prisoners and Hats: the Parity Trick
●●●●○Hard~8 min
- 9Premium
The 100 Lockers
●●●○○Medium~6 min
- 10Premium
Twelve Coins, One Fake
●●●●●Expert~12 min
- 11Premium
How Often Do Clock Hands Overlap?
●●○○○Easy~4 min
- 12Premium
Three Switches, One Bulb
●●●○○Medium~5 min
- 13Premium
The Josephus Problem
●●●●○Hard~9 min
- 14Premium
Ant on a Cube
●●●○○Medium~7 min
- 15Premium
25 Horses, 5 Tracks
●●●●○Hard~8 min
- 16Premium
Crossing the Bridge with One Torch
●●●○○Medium~6 min
- 17Premium
Paying with a Gold Bar
●●●○○Medium~6 min
- 18Premium
Measuring 4 with a 3 and a 5
●●●○○Medium~5 min
- 19Premium
The Game of Nim
●●●●○Hard~9 min
- 20Premium
The Coin-Placing Game
●●●○○Medium~6 min
- 21Premium
The Prisoners and the Lightbulb
●●●●●Expert~12 min
- 22Premium
Splitting Coins Blindfolded
●●●●○Hard~7 min
- 23Premium
Fair Cake Division
●●●○○Medium~6 min
- 24Premium
Twenty Questions
●●○○○Easy~4 min
- 25Premium
The Mislabeled Jars
●●●○○Medium~5 min
- 26Premium
Nine Balls, One Heavy
●●●○○Medium~5 min
- 27Premium
The Mutilated Chessboard
●●●○○Medium~5 min
- 28Premium
Wolf, Goat, and Cabbage
●●●○○Medium~6 min
- 29Premium
Knights and Knaves
●●●○○Medium~5 min
- 30Premium
Hats in a Circle — Guarantee One Correct
●●●●○Hard~7 min
- 31Premium
Russian Roulette: Spin or Not?
●●●○○Medium~6 min
- 32Premium
The King's Wise Men
●●●●○Hard~8 min
- 33Premium
The Camel and the Bananas
●●●○○Medium~7 min
- 34Premium
Cheryl's Birthday
●●●●○Hard~8 min
- 35Premium
The Unexpected Hanging
●●●○○Medium~6 min
- 36Premium
The Handshake Lemma
●●○○○Easy~4 min