🎓 Exam Tomorrow?

We'll build you a custom practice exam.

🐝

Coming Soon!

Theo is building this feature right now. You'll be able to pick your topics, set a time limit, and get a custom mixed exam — no hints, full review at the end.

For now, try the Comprehensive or Timed challenges inside each course!

🎮 Tired of Studying?

Play a game — discover something surprising.

🎯

Subset Sum

Pick numbers that add to the target. Sounds easy...

▶ Play Now

🫧

Independent Set

Select nodes so no two are connected. How many can you pick?

▶ Play Now

🛡️

Vertex Cover

Pick nodes that touch every edge. Use as few as possible.

Coming Soon

📦

Set Cover

Choose fewest subsets to cover every element.

Coming Soon

🔀

3-SAT

Assign true/false to satisfy every clause of 3 literals.

Coming Soon

⚡

Circuit-SAT

Find inputs that make a Boolean circuit output true.

Coming Soon

🌈

No-Rainbow Coloring

Color edges so no triangle uses three different colors.

Coming Soon

🗺️

3-Coloring

Color a graph with 3 colors so no two neighbors match.

Coming Soon

🎒

Knapsack

Pack items to maximize value within a weight limit.

Coming Soon

🔁

Hamiltonian Path

Visit every node exactly once. Find the path.

Coming Soon

🫧 Independent Set

Round 1 of 8

🫧

Pick exactly this many nodes

—

...with no two connected by a line

Theo says:

"You just played Independent Set — one of the classic NP-Complete problems."

You found independent sets by intuition — looking at the graph, noticing clusters, avoiding edges. Write a program to do that for a graph of 1000 nodes? The best known algorithms are exponential in the worst case.

"It is suspicious."

Independent Set is NP-Complete. Interestingly, it's the complement of Vertex Cover — if you found a maximum independent set, you automatically found a minimum vertex cover. Two problems in one. Very suspicious.

🎯 Subset Sum

Round 1 of 8

🎯

Find numbers that add up to

—

Current sum

0

Theo says:

"You just played Subset Sum — one of the most famous problems in all of computer science."

You solved it because humans are good at intuition. But write a program to do what you just did — for a list of 100 numbers? The best known algorithms take exponential time. No one has found a fast one. No one has proved one doesn't exist.

"It is suspicious."

Subset Sum is NP-Complete. That means if you found a fast algorithm for it, you'd solve thousands of other problems at once — including ones that protect your bank account and private messages. Very suspicious indeed.

Want to learn more?

NP-Completeness is covered in Theory of Computation and Algorithm Design. These courses explain the P vs NP question — the biggest unsolved problem in computer science.

Theory of Computation → Algorithm Design →