| 451 | Chimichangas | Alexandru Valeanu | RMI 2015 |      5/5 |
| 452 | Chitooc | Andrei-Cristian Turcu, Eugenie Daniel Posdarascu, Vlad-Mihai Bogdan | ONI 2026, Baraj Seniori, ziua 2 | N/A |
| 453 | Choco | Mugurel Ionut Andreica | Fall Contest #2, SGU 2002 | N/A |
| 454 | Chocolate | Din Folclor | ad-hoc | N/A |
| 455 | Chomp | Stefan Ciobaca | ACM ICPC Faza Nationala 2015 | N/A |
| 456 | Christmas Balls | Edoardo Morassutto | IIOT 2021-22 Runda 2 | N/A |
| 457 | CIA | Bogdan Iordache | InfoOltenia 2018 - Clasele 9 - 10 Echipe | N/A |
| 458 | Ciclu | Radu Berinde | Stelele Informaticii 2003 |      4/5 |
| 459 | Ciclu Eulerian | Arhiva Educationala | Arhiva educationala | N/A |
| 460 | Ciclu hamiltonian de cost minim | Arhiva Educationala | Arhiva Educationala | N/A |
| 461 | Ciclu2 | Adrian Vladu | Happy Birthday Infoarena 2014 | N/A |
| 462 | Cifra | Mircea Bogdan Pasoi | info-arena 1.0 |      1/5 |
| 463 | Cifra Lipsa | Gabriel Bitis | ad-hoc | N/A |
| 464 | Cifra4 | | ad-hoc | N/A |
| 465 | Cifre | Mircea Bogdan Pasoi | preONI 2005 Runda 3 |      3/5 |
| 466 | Cifre 5 | Ciprian Chesca | OJI 2016, clasa a 9-a |      1/5 |
| 467 | Cifre2 | Stelian Ciurea | Lot Sibiu 2011 - Baraj 2 Juniori | N/A |
| 468 | Cifre3 | Mihai Calancea | Infoarena Monthly 2012, Runda 8 | N/A |
| 469 | Cifre4 | Dragos Oprica | ONIS 2014, Runda 1 | N/A |
| 470 | Cifru 2 | Nistor Eugen Mot | Baraj 2006 | N/A |
| 471 | Cifru4 | Carmen Popescu | Lot Juniori 2010 - Baraj 2 | N/A |
| 472 | Cifru5 | Andrei Parvu, Doru Popescu Anastasiu | Lot Baia Mare 2013 - Baraj 1 Seniori | N/A |
| 473 | Cinema | Cristian Cadar | Lista lui Francu | N/A |
| 474 | Ciob | Andrei Poenaru, Mihai-Alexandru Dusmanu | ad-hoc | N/A |
| 475 | Ciocolata | Adrian Panaete | ONI 2014, Baraj | N/A |
| 476 | Ciocolata 2 | Vlad Gavrila | Algoritmiada 2017, Runda 1 | N/A |
| 477 | Circle | | Shumen 2019 Seniori | N/A |
| 478 | Circulatie | Adrian Vladu | Algoritmiada 2013, Runda 2 | N/A |
| 479 | Citylog | Adrian Budau | Algoritmiada 2013, Runda 2 | N/A |
| 480 | Ciuperci | Radu Stefan Voroneanu | .com 2011 | N/A |
| 481 | Ciurul lui Eratosthenes | Arhiva Educationala | ad-hoc | N/A |
| 482 | Ciuruleț | Adrian Budau | ONI 2016, Baraj |      2/5 |
| 483 | Civilizatie | Marcel Dragan | ONI 2016, clasa a 9-a | N/A |
| 484 | Cladiri | Marinel Serban, Stefan Ciobaca | Lot Suceava 2007 | N/A |
| 485 | Clasament | Eugenie Daniel Posdarascu | Algoritmiada 2016 Runda 3 Juniori | N/A |
| 486 | Clasament2 | Denis-Gabriel Mita | Lot Măgurele 2016 - Baraj 6 Seniori | N/A |
| 487 | Clasamente | Ionut Bogdanescu | ACM ICPC Faza Nationala 2015 | N/A |
| 488 | Clasic | Chichirim George, Patrick Sava | Concursul National de Informatica "Adolescent Grigore Moisil" |      1/5 |
| 489 | ClassicTask | Mihai Calancea | Infoarena Monthly 2012, Runda 10 | N/A |
| 490 | Clear | Mugurel Ionut Andreica | Happy Coding 2007 | N/A |
| 491 | Clepsidra | Radu Stefan Voroneanu | ONI 2014, clasele 11-12 |      1/5 |
| 492 | Clepsidru | Ciprian Chesca | OJI 2013, clasa a 9-a | N/A |
| 493 | Cli | Baltatu Andrei, Lucian Bicsi | ONI 2017, Baraj | N/A |
| 494 | Clică de dimensiune maximă | Tudor Muresan | utcn-2021 | N/A |
| 495 | Clici disjuncte total interconectate prin lanțuri | Tudor Muresan | ad-hoc | N/A |
| 496 | Climbers | Catalin Francu | RMI 2018 | N/A |
| 497 | CMMDC | Din Folclor | info-arena 1.0 |      1/5 |
| 498 | Cmmdc2 | Dan Pracsiu, Stelian Ciurea | ONI 2016, clasa a 9-a | N/A |
| 499 | Cmmdcgame | Tamio-Vesa Nakajima | Winter Challenge 2020 | N/A |
| 500 | Cmmmc | Stelian Ciurea | ONI 2010, clasa a 9-a | N/A |