NOI.PH Archive
An assortment of problems used in NOI.PH Eliminations, Finals, and other contests.
Please be patient as we port over our problems to their new home!

Pak Ganern

Pak! Ganern! Pak, pak! Ganern, ganern!

Krazy Karl

Krazy Karl's shopping method involves two dice and a krazy dance. And a sorting algorithm. Because he's kraaaaazy!

Dubidubidapdap

Unlock an n-digit lock code and save your best friend Willie from being hypnotized by the trolls!

Next Generation Currency

Surely these coins aren't THAT hard to tell apart, right?

Skyscaping

Help an architect turn their dream skyline from painting to reality!

The Room

Once you go in... you never come out.

Pering the Platypus

Pering the Platypus, there is no way you can halt my Flashback-inator!

Nice Numbers (Decision)

The bros want to know what numbers are nice. Nice.

Nice Numbers (Counting)

The bros want to know how many numbers are nice. Nice.

Goyo's Game

There's more to this simple game of cards than meets the eye...

...are the Bestagons!

As far as cults go, it could be worse.

The Fibonacci Five-Tuplets

The Pisano sisters agree: all good things in life come in fifths.

The Manga Guide to Competitive Programming

The first ever entry in NOI.PH's Manga Guide series!

ABCs of Men and Women

How can a name tag be so hard to read?

Braid

Everyone should know how to do a simple braid!

I Really Hate Olympiad Algebra

Princess Mattea Oleifera has a dastardly math problem for Neumann Philips.

.img of the Artist as Filipino

True art can be appreciated from any angle.

Osmosis (Version Alpha)

The difficulty of this game is "King of Clubs". Your teamwork and coordination will be tested.

JLO Lawsuit Organization

The Justice League of Ormoc builds a public park. For the good of society!

Ang Dakilang LoomPoints

Apol being wheelchair-bound won't stop him from dancing the Macarena! (aaay!)

Tulkinao

Sukpotao gets pranked by his naughty coworker, Tulkiano.

...are the Bestagons! (Revenge Round)

The bestagon cult is back, and stronger than ever before (just like a hexagon).

The Fibonacci f-Tuplets (Revenge Round)

The Montecillo siblings agree: all good things in life come in twelfths.

Five Needle Telegraph

Telegraphs have existed since even before Morse code, you know?

Parañastack

The only thing better than bananacue is Aling Rostack's bananastacks.

The Distant Future: The Year 2020

Robosums are superior to humans' sums!

Havana

Camilla wants to show off her NOI.PH shirt at a competitive programmers' meetup in Havana (ooh-na-na).

Hello, Awkward Hellos

TFW someone excitedly waves at you, but you didn't wave back because you didn't recognize them. Awkward!

The Last Light of NOI

When all others have fallen, and you're on the brink of defeat... stand your ground! You are the Last Light of NOI!

Biggest Brain Academy

IQ puzzles help your brain to grow nice and wrinkly.

Like the Molave

Not yet, Rizal, not yet. Rest not in peace. Not until this tree problem has been solved!

Git Are Hero

Gideon needs to git gud.

Method of Least Squares

This IS what the method of least squares is about, right?

Astig Runnings

Feel the rhythm, feel the rhyme, come on Philippines, it's biathlon time!

The Manga Guide To Algorithms

Our celebrity chef has got 39 methods to prepare seafood, and she'll make up a million more for you.

Incompetent Interactor

This interactor isn't malicious or adaptive... she's just stupid.

The Astounding Race

Because NOI.PH could really use some physical challenges!

Fast Threerier Transform

It's just as useful as the Fast Fourier Transform, believe me!