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.

id | problem | year | type |
---|---|---|---|

0 | AzaleaA fresh new start, and a new introduction to the NOI.PH! | 2017 | S |

1 | AguinaldoCan you keep track of Emilio's gifts? | 2016 | S |

2 | Who is the oldest?Determine the oldest among friends. | 2014 | PR |

3 | Sharing ChocolatesCan Alvin and Berto share their chocolates fairly? | 2014 | PR |

4 | Sharing Chocolates 2: A Charity EventOur favorite bro-grammers take sharing to a whole new level. | 2014 | F0 |

5 | Sharing Chocolates 3: World RecordAlvin and Berto set out to beat the current chocolate-eating world record. | 2015 | F0 |

6 | On pamelas and pomelosWhich of the Pamelas is closest to the pomelo? | 2014 | F1 |

7 | Body Mass IndexHelp Payton find out whether he should go on a diet. | 2014 | E1 |

8 | A Simple Problem.This is a simple problem. | 2016 | F0 |

9 | Sharing Chocolates 4: A New ChocolateNot so long ago, in a factory not so far far away. | 2016 | F0 |

10 | The Playground FightsHelp the teacher in dealing with kindergarteners. | 2014 | PR |

11 | The Slippery SlopeHelp Cassandra climb the slippery slope! | 2014 | PR |

12 | Jade N. Smith TweetsHow Can This Problem Be Real If Our Eyes Aren’t Real? | 2014 | F0 |

13 | Union FindGuess which algorithm you’ll have to use for this problem! | 2016 | F0 |

14 | FamilyThree sisters discover where to find the true treasure within. | 2014 | E1 |

15 | xoxoFind out who won in a game of xoxo. | 2014 | F1 |

16 | 1 Like = 1 HouseLike! Share! Comment! Change the World! | 2016 | T1 |

17 | The Final SchwelveIt's not The Final Twelve. It's the Final Schwelve. | 2015 | F2 |

18 | Meteor Garden GardenThe boys are fighting over flowers in this Asianovela-inspired problem! | 2016 | E2 |

19 | Extreme TriangleHelp Shan win the game Extreme Triangle. | 2014 | PR |

20 | Path in a MazeFind the path through the maze. | 2014 | F0 |

21 | In or OutIn or out? Can I stay in or do I have to go out? | 2015 | F0 |

22 | Make Gawa This ProgramPlease make gawa this program. | 2015 | T3 |

23 | Onion FindGuess which vegetable this problem is about! | 2016 | F0 |

24 | TataramonIn this problem. we encourage you to be the very best like no one ever was! | 2016 | T2 |

25 | Ham PathHelp Ham the hamster explore Hamsterdam. | 2015 | F0 |

26 | Shake It OffMake the program up as you go read Taylor's problem. | 2016 | F2 |

27 | Awit2DARemixYo!: To The RemixHere's a problem remixing the problem about the new type of poetry form made by Joseph and Mariah. | 2016 | T3 |

28 | A Problem Made By Fools Like MeI think that I shall never see, \\ A poem as lovely as an integer whose hundreds digit is a 3. | 2016 | T1 |

29 | FridayI need a schedule on when to wear my tinfoil hat. | 2015 | T1 |

30 | Rectangle, Diagonal, PerimeterFind the maximum perimeter of a rectangle whose diagonal length is given. | 2014 | E1 |

31 | Bounce Bounce BounceHow many ways can you make a laser bounce bounce bounce? | 2014 | E1 |

32 | Running SamHelp Sam in his self-made mental challenge. | 2015 | F1 |

33 | Stones on a BoardFind out how many ways Jeff can arrange his stones on a board. | 2014 | PR |

34 | Modified FlamesExperience our beloved childhood game with a twist! | 2016 | T2 |

35 | A Packing ProblemCan Miguel pack the cans properly? | 2014 | F1 |

36 | 런데빌런What is the maximum and minimum velocity of 데빌? | 2016 | E1 |

37 | Hasht5 NumbersCompute Hasht5 numbers. | 2016 | T3 |

38 | What Day is It?Never let a rainy day or a Juday get you down! | 2015 | F1 |

39 | Pick-Up BattleCompute scores in the Pick-Up Battle. | 2016 | T1 |

40 | Banana QueueEveryone's going bananas in this exciting work shift! | 2015 | T5 |

41 | Bureaucracy is FunIt's a good thing you don't need to fill in a form every time you make a submission! | 2016 | T2 |

42 | A Simple Problem!This is a simple problem! | 2016 | F1 |

43 | Alien DefenseHelp the inhabitants of Informatica defend against the alien invasion! | 2014 | PR |

44 | Pabebe Girl Cuts CakeHow many ways can a Pabebe Girl cut a rectangular mamon? | 2016 | F1 |

45 | PutogethersHow many mash-ups can the organizers of the annual puto festival make? | 2016 | E1 |

46 | Burning BridgesThe newly-appointed king of the archipelago seems to be the type who likes to burn bridges instead of making friends. | 2014 | E1 |

47 | The King and Queen of Rock and RollCould the interior designer make a proper floor plan following the conditions of the king and queen of Rock and Roll? | 2016 | F1 |

48 | Tinikling 2: The SequelHelp Cleverlyn devise a clever way to adapt to this awkward situation! | 2016 | T3 |

49 | Dili MagpakopyaHonesty is the best policy. | 2015 | F1 |

50 | Paasa NumbersList down all the paasa numbers to make the world a better place! | 2016 | F2 |

51 | Awit2DARemixYo!Joseph and Mariah make a new type of poetry form! | 2015 | E1 |

52 | Candies for EveryoneFind out how candies are distributed among the students. | 2014 | PR |

53 | KawaiiHow many ways can I help Senpai such that I do not produce a bakemono, avoid being itai and not be called a taidana? | 2015 | T3 |

54 | Burning Bridges [Redux]The newly-appointed king of the archipelago seems to be the type who likes to burn bridges instead of making friends. | 2016 | T3 |

55 | Chuva Choo ChooMake your crush feel like he/she is in heaven by giving him/her a mix tape! | 2015 | F2 |

56 | Christopher's Candy ChaosHelp Christopher with a promo for his store. | 2014 | E1 |

57 | Expert TimingThis is the cooking test for NOIPH. | 2016 | E3 |

58 | Bob's ProbBe part of Bob's life-changing experience. | 2014 | PR |

59 | Color GridAfter doing a bunch of stuff, how many cells of each color will the grid have? | 2014 | E1 |

60 | The Questions I Ask MyselfHelp me answer the questions I ask myself. | 2014 | F1 |

61 | A Little Bit FrighteningThis is the sculpting test for NOIPH. | 2016 | E3 |

62 | CheesusI hope you're not lactose-intolerant since this is going to be a very cheesy problem! | 2015 | T2 |

63 | Traveling Supermodel ProblemCan the supermodels find the most fabulous path? | 2014 | PR |

64 | Candies for Everyone [Redux]Find out how candies are distributed among the students. | 2016 | T1 |

65 | Farm WarsFind the optimal strategy for Farm Wars. | 2014 | PR |

66 | This Problem Is So FetchHow much did Rob's opinion change about whether Payton is fetch? | 2015 | E2 |

67 | The Modular WizardHelp Jwrhla compute a number modulo 10^9. | 2016 | T1 |

68 | Balikbayan BoxesOptimize your way around the airport! | 2016 | E2 |

69 | Carps?Pics. | 2016 | F3 |

70 | The RSA CryptosystemGiven an interval, how many numbers satisfy a certain property? | 2014 | F1 |

71 | Christopher's Candy Chaos [Redux]Help Christopher with a promo for his store. | 2015 | T1 |

72 | Bob's Prob [Redux]Be part of Bob's life-changing experience. | 2015 | T2 |

73 | Christmas at NAIAThough 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! | 2016 | E2 |

74 | SupkotaoSpukotao plays a prank in his office. | 2015 | E1 |

75 | Kambyo KardUse your Kambyo Kard wisely. | 2015 | E1 |

76 | The RSA Cryptosystem [Redux]Given an interval, how many numbers satisfy a certain property? | 2015 | T5 |

77 | Lonely People in the WorldWho are the lonely people in the world? | 2015 | T2 |

78 | IntroductionsTake out your social ladders because we're going to go social climbing! | 2016 | T2 |

79 | All for Nine and Nine for AllHow many ways can you win in this new Lunchtime Surprise game? | 2014 | F1 |

80 | Confidential MessageYuo received a message but it was jumbled by some confidential process. | 2016 | F1 |

81 | LolcutsHow cud u cut thees? | 2015 | T4 |

82 | JabahwA very bias problem. | 2016 | F3 |

83 | Kung-Fu FightingThis is the Kung-Fu test for NOIPH. | 2016 | E3 |

84 | The Holiday School PlayLet's assign roles to everyone for the holiday school play! | 2016 | E1 |

85 | Goodbye, Awkward Goodbyes!Help Martin and Martin figure out the correct place to say goodbye. | 2016 | F2 |

86 | Escape the TempleYou got in the temple. Now, how do you get out? | 2015 | T5 |

87 | Tinikling 2 Can a dancer navigate the bamboo pole puzzle to the beat of the music? | 2015 | E2 |

88 | World PeaceHow skillful must you be to retrieve The Artifact of World Peace? | 2014 | F1 |

89 | HeKaSerye#LUNAYSIDRANoongUnangPanahon | 2016 | E2 |

90 | Dishes: How We Do It?How many ways are there to assign dishes to the islands of King Manuel VI's archipelago? | 2016 | E1 |

91 | Chooga Choo ChooGet the scores of Cheech and Chong during their games in a train. | 2015 | F2 |

92 | Color Grid [Redux]After doing a bunch of stuff, how many cells of each color will the grid have? | 2015 | T3 |

93 | Alien Defense DeuxFind the number of laser-strike-free square areas. | 2015 | T1 |

94 | Super BossUse your stick and get some balls to defeat the Super Boss! | 2015 | F2 |

95 | Big BallsGuess the weights of the balls from comparisons. | 2014 | E1 |

96 | Skwishinese Determine how beautiful a Skwishinese word is. | 2014 | E1 |

97 | Zognoid EggsDon't be mad, don't be sad! | 2016 | F3 |

98 | Reverse Trip to JerusalemWinning in Trip to Jerusalem is so two thousand and late. Winning Reverse Trip to Jerusalem is what matters. | 2014 | PR |

99 | Balot BoxesHelp the balot watchers maintain the integrity of the contest. | 2016 | F3 |

100 | World Peace [Redux]How skillful must you be to retrieve The Artifact of World Peace? | 2015 | T4 |

101 | The Tide is HighCompute the productivity of an archipelago when the tide is high. | 2016 | T1 |

102 | Chooga Choo Choo [Redux]Get the scores of Cheech and Chong during their games in a train. | 2016 | T3 |

103 | House ArrestHelp Jejeman find the best lot for his house arrest. | 2015 | E2 |

104 | PWNED BY ANONYMOUS PHPWNED BY ANONYMOUS PH | 2016 | F3 |

105 | Candles for EveryoneBut where's the cake? | 2016 | F2 |

106 | All About the BaseHow many cans do we need to satisfy both Vladonis and Vladiana? | 2015 | T4 |

107 | YumammaHelp Yumamma! | 2016 | T2 |

108 | Fast As LightningThis is the lattice test for NOIPH. | 2016 | E3 |

109 | David CopperfailedFind the number of quadruples where the magic trick works. | 2014 | E1 |

110 | Oprah's Favorite ThingsHow many of each favorite thing should Oprah buy to maximize the gift certificate? | 2014 | F1 |

111 | Back to the FutureYou wanted to build a clock but you ended up with a time machine. Close enough. | 2015 | E2 |

112 | Guardians of the LunaticsAssign the guards to minimize the risk that a lunatic might escape! | 2014 | F1 |

113 | The Grand Noi and ICPC BattleHelp the Noi defeat their wicked foes, the ICPCs. | 2014 | F1 |

1701 | Pak GanernFor every `PAK` there is an equal and opposite `GANERN`. | 2017 | E |

1702 | Copy PastaCan you figure out how many copy pasta resulted in an unfortunate accident? | 2017 | E |

1703 | Ati-atihan Dance PartyAt any given time, how many audience members are engaged by the performers? | 2017 | E |

1704 | Cargo Train to BusanHelp Seok-woo determine how much safe space there is in each carriage so that he can spend his energy wisely. | 2017 | E |

1705 | Mutual FriendzoneHow many mutual friendships in the peculiar friendship network? | 2017 | E |

1706 | Another Packing ProblemCan Miguel answer his packing question? | 2017 | E |

1707 | Hidden PepeIt all started with a hidden Pepe. | 2017 | E |

1708 | The Cheapest ReidHelp James and Nadine go from city A to city B in the cheapest way possible! | 2017 | E |

1709 | GoodboyGoodboy wants to be a good boy by reporting absentees to the school administration. | 2017 | E |

1710 | Tinikling 2: The Sequel 2Help Cleverlyn figure out the minimum number of dance moves her dancers must drop! | 2017 | E |

1711 | FlipTop SortYo! Yo! Yo! Can Abra sort the stack of papers by only flipping the tops? | 2017 | E |

1712 | Lolo GenerosoWill the will be fixed? | 2017 | E |

1713 | The Ultimate RescueRescue Denzel. | 2017 | E |

1714 | A Tale of Two TribesHelp the peace talk organizers prevent the media from destabilizing the two tribes. | 2017 | E |

1715 | Dick and a BoxSee if you're wise enough to know how to solve this problem about Dick and a box. | 2017 | E |

1741 | SuperstitiousSign, seal, and deliver your submission to this problem. | 2017 | F0 |

1742 | Fermat's Last Theorem FINAL NA TALAGAEven Fermat needed to go through a few drafts. | 2017 | F0 |

1743 | Sharing Chocolates 5: The Umpire Strikes BackAy kamatis! | 2017 | F0 |

1744 | Colored Tile PuzzleNyeh heh heh. | 2017 | F0 |

1751 | Bits by Dr DreJuju to the bits with this problem involving Dre. | 2017 | F1 |

1752 | Betty's Bitter Batter BotherHow many ways can Betty put the bitter batter in bowls such that she does not become bothered? | 2017 | F1 |

1753 | The Chenes of The ChorvaFind the sum of the chenes of all the chorva. | 2017 | F1 |

1754 | Bisayaka GridBisayaka Grid? | 2017 | F1 |

1761 | Krazy KarlKrazy Karl has a krazy way of deciding! | 2017 | F2 |

1762 | Gora the ExplorerCan you help Gora and Hector manage to bring blue crystals to their friend waiting in Los Pollos Hermanos? | 2017 | F2 |

1763 | Kapuluan ng KalayaanThis is a ferry interesting problem. | 2017 | F2 |

1764 | Heavy Metal Wall DecorationCan you help the heavy metal fans arrange their heavy metal pipes? | 2017 | F2 |

1771 | Guardians of the Lunatics Vol. 2Prevent the patients from coming a little bit closer to a dangerous wham bam shang-a-lang to their mental health. | 2017 | F3 |

1772 | AgadooA surprising twist unravels as MMORPG players push pineapple by the tree while the fruit sings a hula melody. | 2017 | F3 |

1773 | Spreadsheet GameWhat will the value of the final cell be in this fun spreadsheet game? | 2017 | F3 |

1774 | Constructing a City PlanPersevere! I know you can manage this city problem! | 2017 | F3 |

1775 | Lito Lapida's Lost LapidaLito's tombstone was stolen by heartless thieves! It seems he was right in saying: saging lang ang may puso. | 2017 | F3 |

1801 | DubidubidapdapBee-beep beep beep beep beep beep beep beep! | 2018 | E |

1802 | Congratulations Bimb!Help Mommy Kris make a tarp of Bimb's best grades. | 2018 | E |

1803 | Palacañang PortraitDuring his European tour, President Palaka takes a picture at Frague. | 2018 | E |

1804 | He Attac But Also ProtecGet you a Bato that can do both. | 2018 | E |

1805 | Extreme AmbulationThe intent is to provide players with a sense of pride and accomplishment. | 2018 | E |

1806 | Lodi PetmaluWerpa! | 2018 | E |

1807 | TsunderefsHelp the kitchen appliances get as far away from each other as possible. | 2018 | E |

1808 | Ika-6 na OrdinansaIt comes after the ika-5 na ordinansa, and before the ika-7 na ordinansa. | 2018 | E |

1809 | Number PartyCan I get your number? | 2018 | E |

1810 | Help Your Friend Come OutIt is terrifying to come out of closets. Can you help your friend come out? | 2018 | E |

1811 | Cooking by the BookYou know you can't be lazy! The cake will end up crazy! | 2018 | E |

1812 | Robin vs The PenguinThe most ambitious crossover event in NOI.PH history. | 2018 | E |

1813 | Keribells and KeriboomboomCan you solve this problem? Kering-keri yan! | 2018 | E |

1814 | Pakain ng PahiyasKeeping the traditions of the Pahiyas Festival going! | 2018 | E |

1815 | Breakdown BudgetIn which Harry rides the train to show that he understands the everyday plight of commuters. | 2018 | E |

1841 | Studying DiplomacySpy on text messages! What a relevant application of technology. | 2018 | F0 |

1842 | The Speedup LoopMaking a program run faster is as easy as removing a single character. | 2018 | F0 |

1843 | Yumamma IIYumamma's so smart, she can easily solve this problem. | 2018 | F0 |

1844 | Sharing Chocolates 6: Return of the JudayThe worse out of the original Sharing Chocolates trilogy. | 2018 | F0 |

1851 | Voltes GroupThe superelectromagnetic robots get stuck together. | 2018 | F1 |

1852 | Global WarmingNot a real problem. | 2018 | F1 |

1853 | Thrust TrialsHelp Vanilla and Spwet's engineers in their top-secret spaceship project. | 2018 | F1 |

1854 | Lean on MeWhat do you call flying planks? Plywood. | 2018 | F1 |

1855 | Boomerang GadgetMy only healing is that you switch this gadget into healing mode. | 2018 | F1 |

1861 | Merging and MissilesThe robots use their superelectromagnetism to stick alien ships together. | 2018 | F2 |

1862 | Sister SpaceshipsVehicles that transform. Definitely not something I've heard before. | 2018 | F2 |

1863 | Late-Night LitteringWill The Cleaner Alien catch The Illegal Alien? | 2018 | F2 |

1864 | Backbreaking BreakoutPresident Froggy is trapped in jail! Help him escape! I mean, if you want to. | 2018 | F2 |

1865 | People PowerRally in EDSA! Make a stand! Get people frustrated! Then find the sum of the frustrations of a subarray of the rallyists! | 2018 | F2 |

1871 | ParañaqueueParañaqueue, queue, queue, push pineapple, shake the tree. | 2018 | F3 |

1872 | Mood SwingsArrange songs in a radio station to maximize profit, because we're all greedy capitalists. | 2018 | F3 |

1873 | Socrates and PlateauMaybe if you ask the right questions, you'll learn the method to solving this problem. | 2018 | F3 |

1874 | Mga Anak ng TokwaThese reproductive tofu have a strange family tree... | 2018 | F3 |

1875 | Sugar RollYema one and only. | 2018 | F3 |

1876 | We Are Number OneHere's a little lesson in trickery. This is going down in history. | 2018 | F3 |

1901 | Next Generation CurrencyThe solution to coins that look the same? Make everyone wear high-tech glasses. | 2019 | E |

1902 | Anion FindIn Tagalog, "what is that" translates to "anion". | 2019 | E |

1903 | Evening Gown"Fortunately, Catriona is fireproof, immune to lava, and can walk on liquids." | 2019 | E |

1904 | Aswang Immortal - Trivia!Answer interesting questions about Filipino mythology! | 2019 | E |

1905 | Exchange GiftWill Barbie and Jak's exchange gift proceed this Christmas? | 2019 | E |

1906 | Lots of CookiesGet those cookies, get those cookies, get those cookies... | 2019 | E |

1907 | Dagohoy Rock Lapu-Lapu BoogieThe Sugbo-anons and the Bol-anons have agreed to do a dance number together. | 2019 | E |

1908 | 最終審判お前はもう裁かれる。 | 2019 | E |

1909 | Spratly Islands TourTour the other countries around the Spratly Islands for fishin—no. Minin—uh. Gas explorati—research. Just research. | 2019 | E |

1910 | SkyscapingGo on and try to tear me down, I will be rising from the ground. | 2019 | E |

1911 | Super RangersWe've never had a problem on merging robots before. Nope. Not at all. | 2019 | E |

1912 | ReMotionHow do I make a story? Let me count the ways... | 2019 | E |

1913 | Yet Another Packing ProblemAlthough Miguel used to specialize at packing sopas, he got a promotion and is now packing pasta. | 2019 | E |

1914 | Almost OriginalWe didn't write a story for this problem. Not even a witty joke. You won't get one here either. | 2019 | E |

1941 | Sharing Chocolates 7: The Force Equals Mass Times AccelerationThe mass times acceleration awakens. | 2019 | F0 |

1942 | Totally Not RobotsYou are a REGULAR HUMAN BEING. Extract sentences from your UTTERANCE QUEUE. | 2019 | F0 |

1943 | Mystery FunctionDoes every finite group appear as the Galois group of some Galois extension of the rationals, and not just cyclic groups? | 2019 | F0 |

1944 | City MapMake a spicy city map for your friends' parties. | 2019 | F0 |

1945 | Bato Bato SplitPick and split! | 2019 | F0 |

1951 | Magkaribal sa Arnibal"When the MRT arrives, each person simultaneously throws their taho." | 2019 | F1 |

1952 | Baby Come BakBring your baby back to bakuna. | 2019 | F1 |

1953 | Tower BloxxStack the tower blocks in the right order. | 2019 | F1 |

1954 | The RoomDo you know what a downdog is? It's the opposite of an upcat. | 2019 | F1 |

1955 | Sumbong CentersHelp construct Sumbong Centers in Siyudad City. | 2019 | F1 |

1961 | Illegal LoggingAre you familiar with what Filipinos say about illegal logging? | 2019 | F2 |

1962 | BATIBotsThe Brainy Automated Transcendental Intelligent Bots guard Mactan from colonizers. | 2019 | F2 |

1963 | Mr. KupidoHelp Mr. Kupido make a group of people fall in one-sided love. | 2019 | F2 |

1964 | Sorting the PlanetsFollow the example of Kevin, the cosmic maintainer of the universe. | 2019 | F2 |

1965 | CartogramCan you make a map by following following following these instructions? | 2019 | F2 |

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.