Hello, Codeforces!
We are glad to invite you to take part in Hello 2026, which will start on Wednesday, January 7, 2026 at 22:35UTC+8. You will be given 9 problems and 3 hours to solve them. At least one problem will be interactive, so please make sure to read the guide for interactive problems before the contest. This round is open and rated for everyone.
Problems are authored by wangmarui, Gold14526, Hoks_, Neil_Qian, Network_Error, jiazhichen844 and xvchongyv.
We would like to thank:
- Proof_by_QED for his wonderful coordination.
- Alexdat2000 for Russian translation.
- Geothermal, StarSilk, and Dominater069 for nutella testing.
- Mindeveloped, ETO_leader, nldr, max0810, A_G, _istil, ian_HLX, nifeshe, paulzrm, sammyuri, catgirl and Intellegent for red testing.
- cuteSubtask, LucaLucaM, cry, Genius_Star_rgw, Friedrich, incra, lkrqwq, LaDeX, pichax, shiny_shine, efishel, Edeeva, Register, omsincoconut, AksLolCoding, Watersphere, Lilypad, tzl_Dedicatus545, Caylex and waauto for yellow testing.
- NATO, Cfz_qwq, gotexans, gza, wuhudsm, madlogic and Heartquake for purple testing.
- tybbs, larush, pianapolataa, Terminator-XII, hollis_yang, Nukumizu-Anna, shengxuanyi, chromate00 and cby_ for blue testing.
- wizardMarshall, Solwek, sztcodeforces and lottle1212 for cyan testing.
- yaotianhao0906, lovelyfish and YSY_ for green testing.
- chenzhishuo2012 and Lvl200GoldenDragon for gray testing.
- Lynette_D for unrated testing.
- MikeMirzayanov and KAN for the great Codeforces and Polygon platforms.
- You for participating in this round.
