Past Problems

Here are all the past problems for the NOI.PH. Trying this out should give you a glimpse of what NOI problems are like. If you get stumped, you should prepare by reading the resources on this website.

If you can’t access the past problems, click here.

idproblemyeartype
0Azalea
A fresh new start, and a new introduction to the NOI.PH!
2017S
1Aguinaldo
Can you keep track of Emilio's gifts?
2016S
2Who is the oldest?
Determine the oldest among friends.
2014PR
3Sharing Chocolates
Can Alvin and Berto share their chocolates fairly?
2014PR
4Sharing Chocolates 2: A Charity Event
Our favorite bro-grammers take sharing to a whole new level.
2014F0
5Sharing Chocolates 3: World Record
Alvin and Berto set out to beat the current chocolate-eating world record.
2015F0
6On pamelas and pomelos
Which of the Pamelas is closest to the pomelo?
2014F1
7Body Mass Index
Help Payton find out whether he should go on a diet.
2014E1
8A Simple Problem.
This is a simple problem.
2016F0
9Sharing Chocolates 4: A New Chocolate
Not so long ago, in a factory not so far far away.
2016F0
10The Playground Fights
Help the teacher in dealing with kindergarteners.
2014PR
11The Slippery Slope
Help Cassandra climb the slippery slope!
2014PR
12Jade N. Smith Tweets
How Can This Problem Be Real If Our Eyes Aren’t Real?
2014F0
13Union Find
Guess which algorithm you’ll have to use for this problem!
2016F0
14Family
Three sisters discover where to find the true treasure within.
2014E1
15xoxo
Find out who won in a game of xoxo.
2014F1
161 Like = 1 House
Like! Share! Comment! Change the World!
2016T1
17The Final Schwelve
It's not The Final Twelve. It's the Final Schwelve.
2015F2
18Meteor Garden Garden
The boys are fighting over flowers in this Asianovela-inspired problem!
2016E2
19Extreme Triangle
Help Shan win the game Extreme Triangle.
2014PR
20Path in a Maze
Find the path through the maze.
2014F0
21In or Out
In or out? Can I stay in or do I have to go out?
2015F0
22Make Gawa This Program
Please make gawa this program.
2015T3
23Onion Find
Guess which vegetable this problem is about!
2016F0
24Tataramon
In this problem. we encourage you to be the very best like no one ever was!
2016T2
25Ham Path
Help Ham the hamster explore Hamsterdam.
2015F0
26Shake It Off
Make the program up as you go read Taylor's problem.
2016F2
27Awit2DARemixYo!: To The Remix
Here's a problem remixing the problem about the new type of poetry form made by Joseph and Mariah.
2016T3
28A Problem Made By Fools Like Me
I think that I shall never see, \\ A poem as lovely as an integer whose hundreds digit is a 3.
2016T1
29Friday
I need a schedule on when to wear my tinfoil hat.
2015T1
30Rectangle, Diagonal, Perimeter
Find the maximum perimeter of a rectangle whose diagonal length is given.
2014E1
31Bounce Bounce Bounce
How many ways can you make a laser bounce bounce bounce?
2014E1
32Running Sam
Help Sam in his self-made mental challenge.
2015F1
33Stones on a Board
Find out how many ways Jeff can arrange his stones on a board.
2014PR
34Modified Flames
Experience our beloved childhood game with a twist!
2016T2
35A Packing Problem
Can Miguel pack the cans properly?
2014F1
36런데빌런
What is the maximum and minimum velocity of 데빌?
2016E1
37Hasht5 Numbers
Compute Hasht5 numbers.
2016T3
38What Day is It?
Never let a rainy day or a Juday get you down!
2015F1
39Pick-Up Battle
Compute scores in the Pick-Up Battle.
2016T1
40Banana Queue
Everyone's going bananas in this exciting work shift!
2015T5
41Bureaucracy is Fun
It's a good thing you don't need to fill in a form every time you make a submission!
2016T2
42A Simple Problem!
This is a simple problem!
2016F1
43Alien Defense
Help the inhabitants of Informatica defend against the alien invasion!
2014PR
44Pabebe Girl Cuts Cake
How many ways can a Pabebe Girl cut a rectangular mamon?
2016F1
45Putogethers
How many mash-ups can the organizers of the annual puto festival make?
2016E1
46Burning Bridges
The newly-appointed king of the archipelago seems to be the type who likes to burn bridges instead of making friends.
2014E1
47The King and Queen of Rock and Roll
Could the interior designer make a proper floor plan following the conditions of the king and queen of Rock and Roll?
2016F1
48Tinikling 2: The Sequel
Help Cleverlyn devise a clever way to adapt to this awkward situation!
2016T3
49Dili Magpakopya
Honesty is the best policy.
2015F1
50Paasa Numbers
List down all the paasa numbers to make the world a better place!
2016F2
51Awit2DARemixYo!
Joseph and Mariah make a new type of poetry form!
2015E1
52Candies for Everyone
Find out how candies are distributed among the students.
2014PR
53Kawaii
How many ways can I help Senpai such that I do not produce a bakemono, avoid being itai and not be called a taidana?
2015T3
54Burning Bridges [Redux]
The newly-appointed king of the archipelago seems to be the type who likes to burn bridges instead of making friends.
2016T3
55Chuva Choo Choo
Make your crush feel like he/she is in heaven by giving him/her a mix tape!
2015F2
56Christopher's Candy Chaos
Help Christopher with a promo for his store.
2014E1
57Expert Timing
This is the cooking test for NOIPH.
2016E3
58Bob's Prob
Be part of Bob's life-changing experience.
2014PR
59Color Grid
After doing a bunch of stuff, how many cells of each color will the grid have?
2014E1
60The Questions I Ask Myself
Help me answer the questions I ask myself.
2014F1
61A Little Bit Frightening
This is the sculpting test for NOIPH.
2016E3
62Cheesus
I hope you're not lactose-intolerant since this is going to be a very cheesy problem!
2015T2
63Traveling Supermodel Problem
Can the supermodels find the most fabulous path?
2014PR
64Candies for Everyone [Redux]
Find out how candies are distributed among the students.
2016T1
65Farm Wars
Find the optimal strategy for Farm Wars.
2014PR
66This Problem Is So Fetch
How much did Rob's opinion change about whether Payton is fetch?
2015E2
67The Modular Wizard
Help Jwrhla compute a number modulo 10^9.
2016T1
68Balikbayan Boxes
Optimize your way around the airport!
2016E2
69Carps?
Pics.
2016F3
70The RSA Cryptosystem
Given an interval, how many numbers satisfy a certain property?
2014F1
71Christopher's Candy Chaos [Redux]
Help Christopher with a promo for his store.
2015T1
72Bob's Prob [Redux]
Be part of Bob's life-changing experience.
2015T2
73Christmas at NAIA
Though it was once rated as the worst airport, NAIA personnel have brushed that reputation aside by being generous to the travelers, especially this holiday season!
2016E2
74Supkotao
Spukotao plays a prank in his office.
2015E1
75Kambyo Kard
Use your Kambyo Kard wisely.
2015E1
76The RSA Cryptosystem [Redux]
Given an interval, how many numbers satisfy a certain property?
2015T5
77Lonely People in the World
Who are the lonely people in the world?
2015T2
78Introductions
Take out your social ladders because we're going to go social climbing!
2016T2
79All for Nine and Nine for All
How many ways can you win in this new Lunchtime Surprise game?
2014F1
80Confidential Message
Yuo received a message but it was jumbled by some confidential process.
2016F1
81Lolcuts
How cud u cut thees?
2015T4
82Jabahw
A very bias problem.
2016F3
83Kung-Fu Fighting
This is the Kung-Fu test for NOIPH.
2016E3
84The Holiday School Play
Let's assign roles to everyone for the holiday school play!
2016E1
85Goodbye, Awkward Goodbyes!
Help Martin and Martin figure out the correct place to say goodbye.
2016F2
86Escape the Temple
You got in the temple. Now, how do you get out?
2015T5
87Tinikling 2
Can a dancer navigate the bamboo pole puzzle to the beat of the music?
2015E2
88World Peace
How skillful must you be to retrieve The Artifact of World Peace?
2014F1
89HeKaSerye
#LUNAYSIDRANoongUnangPanahon
2016E2
90Dishes: How We Do It?
How many ways are there to assign dishes to the islands of King Manuel VI's archipelago?
2016E1
91Chooga Choo Choo
Get the scores of Cheech and Chong during their games in a train.
2015F2
92Color Grid [Redux]
After doing a bunch of stuff, how many cells of each color will the grid have?
2015T3
93Alien Defense Deux
Find the number of laser-strike-free square areas.
2015T1
94Super Boss
Use your stick and get some balls to defeat the Super Boss!
2015F2
95Big Balls
Guess the weights of the balls from comparisons.
2014E1
96Skwishinese
Determine how beautiful a Skwishinese word is.
2014E1
97Zognoid Eggs
Don't be mad, don't be sad!
2016F3
98Reverse Trip to Jerusalem
Winning in Trip to Jerusalem is so two thousand and late. Winning Reverse Trip to Jerusalem is what matters.
2014PR
99Balot Boxes
Help the balot watchers maintain the integrity of the contest.
2016F3
100World Peace [Redux]
How skillful must you be to retrieve The Artifact of World Peace?
2015T4
101The Tide is High
Compute the productivity of an archipelago when the tide is high.
2016T1
102Chooga Choo Choo [Redux]
Get the scores of Cheech and Chong during their games in a train.
2016T3
103House Arrest
Help Jejeman find the best lot for his house arrest.
2015E2
104PWNED BY ANONYMOUS PH
PWNED BY ANONYMOUS PH
2016F3
105Candles for Everyone
But where's the cake?
2016F2
106All About the Base
How many cans do we need to satisfy both Vladonis and Vladiana?
2015T4
107Yumamma
Help Yumamma!
2016T2
108Fast As Lightning
This is the lattice test for NOIPH.
2016E3
109David Copperfailed
Find the number of quadruples where the magic trick works.
2014E1
110Oprah's Favorite Things
How many of each favorite thing should Oprah buy to maximize the gift certificate?
2014F1
111Back to the Future
You wanted to build a clock but you ended up with a time machine. Close enough.
2015E2
112Guardians of the Lunatics
Assign the guards to minimize the risk that a lunatic might escape!
2014F1
113The Grand Noi and ICPC Battle
Help the Noi defeat their wicked foes, the ICPCs.
2014F1
1701Pak Ganern
For every `PAK` there is an equal and opposite `GANERN`.
2017E
1702Copy Pasta
Can you figure out how many copy pasta resulted in an unfortunate accident?
2017E
1703Ati-atihan Dance Party
At any given time, how many audience members are engaged by the performers?
2017E
1704Cargo Train to Busan
Help Seok-woo determine how much safe space there is in each carriage so that he can spend his energy wisely.
2017E
1705Mutual Friendzone
How many mutual friendships in the peculiar friendship network?
2017E
1706Another Packing Problem
Can Miguel answer his packing question?
2017E
1707Hidden Pepe
It all started with a hidden Pepe.
2017E
1708The Cheapest Reid
Help James and Nadine go from city A to city B in the cheapest way possible!
2017E
1709Goodboy
Goodboy wants to be a good boy by reporting absentees to the school administration.
2017E
1710Tinikling 2: The Sequel 2
Help Cleverlyn figure out the minimum number of dance moves her dancers must drop!
2017E
1711FlipTop Sort
Yo! Yo! Yo! Can Abra sort the stack of papers by only flipping the tops?
2017E
1712Lolo Generoso
Will the will be fixed?
2017E
1713The Ultimate Rescue
Rescue Denzel.
2017E
1714A Tale of Two Tribes
Help the peace talk organizers prevent the media from destabilizing the two tribes.
2017E
1715Dick and a Box
See if you're wise enough to know how to solve this problem about Dick and a box.
2017E
1741Superstitious
Sign, seal, and deliver your submission to this problem.
2017F0
1742Fermat's Last Theorem FINAL NA TALAGA
Even Fermat needed to go through a few drafts.
2017F0
1743Sharing Chocolates 5: The Umpire Strikes Back
Ay kamatis!
2017F0
1744Colored Tile Puzzle
Nyeh heh heh.
2017F0
1751Bits by Dr Dre
Juju to the bits with this problem involving Dre.
2017F1
1752Betty's Bitter Batter Bother
How many ways can Betty put the bitter batter in bowls such that she does not become bothered?
2017F1
1753The Chenes of The Chorva
Find the sum of the chenes of all the chorva.
2017F1
1754Bisayaka Grid
Bisayaka Grid?
2017F1
1761Krazy Karl
Krazy Karl has a krazy way of deciding!
2017F2
1762Gora the Explorer
Can you help Gora and Hector manage to bring blue crystals to their friend waiting in Los Pollos Hermanos?
2017F2
1763Kapuluan ng Kalayaan
This is a ferry interesting problem.
2017F2
1764Heavy Metal Wall Decoration
Can you help the heavy metal fans arrange their heavy metal pipes?
2017F2
1771Guardians of the Lunatics Vol. 2
Prevent the patients from coming a little bit closer to a dangerous wham bam shang-a-lang to their mental health.
2017F3
1772Agadoo
A surprising twist unravels as MMORPG players push pineapple by the tree while the fruit sings a hula melody.
2017F3
1773Spreadsheet Game
What will the value of the final cell be in this fun spreadsheet game?
2017F3
1774Constructing a City Plan
Persevere! I know you can manage this city problem!
2017F3
1775Lito Lapida's Lost Lapida
Lito's tombstone was stolen by heartless thieves! It seems he was right in saying: saging lang ang may puso.
2017F3
1801Dubidubidapdap
Bee-beep beep beep beep beep beep beep beep!
2018E
1802Congratulations Bimb!
Help Mommy Kris make a tarp of Bimb's best grades.
2018E
1803Palacañang Portrait
During his European tour, President Palaka takes a picture at Frague.
2018E
1804He Attac But Also Protec
Get you a Bato that can do both.
2018E
1805Extreme Ambulation
The intent is to provide players with a sense of pride and accomplishment.
2018E
1806Lodi Petmalu
Werpa!
2018E
1807Tsunderefs
Help the kitchen appliances get as far away from each other as possible.
2018E
1808Ika-6 na Ordinansa
It comes after the ika-5 na ordinansa, and before the ika-7 na ordinansa.
2018E
1809Number Party
Can I get your number?
2018E
1810Help Your Friend Come Out
It is terrifying to come out of closets. Can you help your friend come out?
2018E
1811Cooking by the Book
You know you can't be lazy! The cake will end up crazy!
2018E
1812Robin vs The Penguin
The most ambitious crossover event in NOI.PH history.
2018E
1813Keribells and Keriboomboom
Can you solve this problem? Kering-keri yan!
2018E
1814Pakain ng Pahiyas
Keeping the traditions of the Pahiyas Festival going!
2018E
1815Breakdown Budget
In which Harry rides the train to show that he understands the everyday plight of commuters.
2018E
1841Studying Diplomacy
Spy on text messages! What a relevant application of technology.
2018F0
1842The Speedup Loop
Making a program run faster is as easy as removing a single character.
2018F0
1843Yumamma II
Yumamma's so smart, she can easily solve this problem.
2018F0
1844Sharing Chocolates 6: Return of the Juday
The worse out of the original Sharing Chocolates trilogy.
2018F0
1851Voltes Group
The superelectromagnetic robots get stuck together.
2018F1
1852Global Warming
Not a real problem.
2018F1
1853Thrust Trials
Help Vanilla and Spwet's engineers in their top-secret spaceship project.
2018F1
1854Lean on Me
What do you call flying planks? Plywood.
2018F1
1855Boomerang Gadget
My only healing is that you switch this gadget into healing mode.
2018F1
1861Merging and Missiles
The robots use their superelectromagnetism to stick alien ships together.
2018F2
1862Sister Spaceships
Vehicles that transform. Definitely not something I've heard before.
2018F2
1863Late-Night Littering
Will The Cleaner Alien catch The Illegal Alien?
2018F2
1864Backbreaking Breakout
President Froggy is trapped in jail! Help him escape! I mean, if you want to.
2018F2
1865People Power
Rally in EDSA! Make a stand! Get people frustrated! Then find the sum of the frustrations of a subarray of the rallyists!
2018F2
1871Parañaqueue
Parañaqueue, queue, queue, push pineapple, shake the tree.
2018F3
1872Mood Swings
Arrange songs in a radio station to maximize profit, because we're all greedy capitalists.
2018F3
1873Socrates and Plateau
Maybe if you ask the right questions, you'll learn the method to solving this problem.
2018F3
1874Mga Anak ng Tokwa
These reproductive tofu have a strange family tree...
2018F3
1875Sugar Roll
Yema one and only.
2018F3
1876We Are Number One
Here's a little lesson in trickery. This is going down in history.
2018F3
1901Next Generation Currency
The solution to coins that look the same? Make everyone wear high-tech glasses.
2019E
1902Anion Find
In Tagalog, "what is that" translates to "anion".
2019E
1903Evening Gown
"Fortunately, Catriona is fireproof, immune to lava, and can walk on liquids."
2019E
1904Aswang Immortal - Trivia!
Answer interesting questions about Filipino mythology!
2019E
1905Exchange Gift
Will Barbie and Jak's exchange gift proceed this Christmas?
2019E
1906Lots of Cookies
Get those cookies, get those cookies, get those cookies...
2019E
1907Dagohoy Rock Lapu-Lapu Boogie
The Sugbo-anons and the Bol-anons have agreed to do a dance number together.
2019E
1908最終審判
お前はもう裁かれる。
2019E
1909Spratly Islands Tour
Tour the other countries around the Spratly Islands for fishin—no. Minin—uh. Gas explorati—research. Just research.
2019E
1910Skyscaping
Go on and try to tear me down, I will be rising from the ground.
2019E
1911Super Rangers
We've never had a problem on merging robots before. Nope. Not at all.
2019E
1912ReMotion
How do I make a story? Let me count the ways...
2019E
1913Yet Another Packing Problem
Although Miguel used to specialize at packing sopas, he got a promotion and is now packing pasta.
2019E
1914Almost Original
We didn't write a story for this problem. Not even a witty joke. You won't get one here either.
2019E
1941Sharing Chocolates 7: The Force Equals Mass Times Acceleration
The mass times acceleration awakens.
2019F0
1942Totally Not Robots
You are a REGULAR HUMAN BEING. Extract sentences from your UTTERANCE QUEUE.
2019F0
1943Mystery Function
Does every finite group appear as the Galois group of some Galois extension of the rationals, and not just cyclic groups?
2019F0
1944City Map
Make a spicy city map for your friends' parties.
2019F0
1945Bato Bato Split
Pick and split!
2019F0
1951Magkaribal sa Arnibal
"When the MRT arrives, each person simultaneously throws their taho."
2019F1
1952Baby Come Bak
Bring your baby back to bakuna.
2019F1
1953Tower Bloxx
Stack the tower blocks in the right order.
2019F1
1954The Room
Do you know what a downdog is? It's the opposite of an upcat.
2019F1
1955Sumbong Centers
Help construct Sumbong Centers in Siyudad City.
2019F1
1961Illegal Logging
Are you familiar with what Filipinos say about illegal logging?
2019F2
1962BATIBots
The Brainy Automated Transcendental Intelligent Bots guard Mactan from colonizers.
2019F2
1963Mr. Kupido
Help Mr. Kupido make a group of people fall in one-sided love.
2019F2
1964Sorting the Planets
Follow the example of Kevin, the cosmic maintainer of the universe.
2019F2
1965Cartogram
Can you make a map by following following following these instructions?
2019F2

Legend:

  • S Sample problem. Created only for a series of tutorial posts (this and this).
  • PR Practice problems released before the Elimination Round. (Only for 2014)
  • Tx Training problems released one week before each Elimination Round x(Only for 2015)
  • Ex Elimination Round problem. x signifies which round. If there is only one round, x is omitted.
  • Fx Final Round problem. x signifies which round. If x = 0, then it was during the finals practice round.