Hello CF!

I think many of you, in particular IOI participants, can not find a good, clear solutions of IOI problems, so I decided to create a blog where we will publish a problem then find solution for it and start to solve next problem (like on AOPS).

Let me begin — IOI 2006 B. Pyramid.

Name	CF Handle	Country	Previous IOIs
Román Castellarin	ponysalvaje	Argentina	2013 2014
Ariel Nowik	ariel.nowik	Argentina	No Participation
Martin Mirakyan	Martin97	Armenia	No Participation
Mushegh Shahinyan	MyLeg	Armenia	2014
Albert Gevorgyan	albertg	Armenia	No Participation
Eduard Grigoryan	edogrigqv2	Armenia	2010, 2011, 2013, 2014
Florian Leimgruber	fleimgruber	Austria	2014
Gary Ye	GaryYe	Austria	2013 , 2014
Peter Ralbovsky	peto159	Austria	2013, 2014
Simon Lehner-Dittenberger		Austria	No Participation
Nur Muhammad Shafiullah	LamePrince	Bangladesh	2012
Hasib Al Muhaimin	hasib	Bangladesh	2013 2014
Labib Rashid	Labib666	Bangladesh	2013 2014
Imran Hasan	SkullKnight	Bangladesh	No Participation
Nikita Sazanovich	Nik_Storm_2010	Belarus	No Participation
Alex Vistyazh	netman	Belarus	2014
Barbara Kuskova	kuskova	Belarus	2014
Ilya Medyanikov	Ferathorn	Belarus	No Participation
Mattéo Couplet	mcouplet	Belgium	No Participation
Damien Galant	damien_g	Belgium	2014
Robin Jadoul		Belgium	No Participation
Nico Ekkart	nicoekkart	Belgium	No Participation
Marcelo Zeballos	marcelozeballos	Bolivia	No Participation
Ronaldo Franco Jaldin	rony	Bolivia	2014
Arthur Pratti Dadalto	arthurpd	Brazil	2014
Mateus Bezrutchka	m_bezrutchka	Brazil	2014
Lucca Morais de Arruda Siaudzionis	luccasiau	Brazil	No Participation
Murilo Corato Zanarella	murilocz	Brazil	No Participation
Hristo Venev	mustrumr	Bulgaria	2012 ,2013 , 2014
Encho Mishinev	Enchom	Bulgaria	2013 2014
Daniel Atanasov		Bulgaria	No Participation
Kristian Tsaklev	krisits	Bulgaria	No Participation
Farbod Yadegarian	FarbodY	Canada	No Participation
Yikuan (Timothy) Li	FatalEagle	Canada	2014
Ben Zhang	Kuroba	Canada	2014
Jacob Jackson	zxqfl	Canada	2014
Yanyi Liu	lyy	China	No Participation
Xiaochen Lu	Ruchiose	China	No Participation
Yuhao Du	jqdai0815	China	No Participation
Hengjie Zhang	zhj	China	No Participation
Juan Sebastian Chaves	Chaves	Colombia	2014
Domagoj Bradac	DBradac	Croatia	No Participation
Tonko Sabolcec	tonkosi	Croatia	No Participation
Mihael Liskij	Mihaell	Croatia	No Participation
Ivan Lazaric	IvL	Croatia	2013
Alexander Bestard Rivera	bestard	Cuba	No Participation
Michael Gonzáles	Mjgonzales	Dominican Republic	No Participation
Manuel David Sánchez Suero	tecnomaster999	Dominican Republic	No Participation
Alejandra Martínez Jiménez	alejandra_244	Dominican Republic	No Participation
Sami Kalliomäki	Scintillo	Finland	2012, 2013 , 2014
Tuukka Korhonen	Laakeri	Finland	No Participation
Henrik Lievonen	Hennkka	Finland	2013, 2014
Kalle Luopajärvi	kllp	Finland	2013 , 2014
Alexander Tskhovrebov	alexandre	Georgia	No Participation
Georgy Skhirtladze	gskhirtladze	Georgia	2014
Elene Machaidze	emachaidze	Georgia	2014
Giorgi Kldiashvili	GiorgiKldiashvili	Georgia	No Participation
Aristofanis Rontogiannis	mentalist	Greece	2014
Panagiotis Kostopanagiotis	infinity	Greece	2013
Konstantinos Agiannis		Greece	No Participation
Emanuel Mihalainas		Greece	No Participation
Tanay Kothari	Tanay1998	India	No Participation
Malvika Raj Joshi	a0666	India	2014
Arjun P	Superty	India	No Participation
Kushagra Juneja		India	No Participation
Muhammad Ayaz Dzulfikar	ayaze	Indonesia	No Participation
Michael Wibawa	M_W	Indonesia	No Participation
Agus Sentosa Hermawan	aguss787	Indonesia	No Participation
Stacia Edina Johanna		Indonesia	No Participation
Francesco Milizia	fram	Italy	2014
Marco Donadoni	mark03	Italy	No Participation
Filippo Baroni	Delfad0r	Italy	No Participation
Peiman Jabbarzade	JeBeK	Iran	No Participation
Ali Haghani	Haghani	Iran	No Participation
Ali Bahjati	LiTi	Iran	No Participation
Amir Keivan Mohtashami	matrix	Iran	No Participation
Sami Daoud	daoudsammy1	Jordan	No Participation
Aleksejs Zajakins	Alex_2oo8	Latvia	2014
Kristaps Čivkulis	how_to_become_purple	Latvia	2014
Ingus Jānis Pretkalniņš	Ingus	Latvia	2014
Aleksejs Popovs	popoffka	Latvia	2011, 2012 , 2013 , 2014
Azret Kenzhaliev	Azret	Kyrgyzstan	No Participation
Kadyrbek Narmamatov	SEFI2	Kyrgyzstan	2014
Erkin Matkaziev	Erkin97	Kyrgyzstan	2014
Zarlyk Jusubaliev	heavenly_phoenix	Kyrgyzstan	No Participation
Kliment Serafimov		Macedonia	2012 2013 2014
Hristijan Gjorshevski		Macedonia	No Participation
Mihail Denkovski		Macedonia	No Participation
Juan Carlos Sigler Priego	Juanito98	Mexico	No Participation
Carlos Galeana Hernandez	charlyhlms	Mexico	No Participation
Angel David Ortega Ramirez	blak_dragon	Mexico	No Participation
Emmanuel Antonio Cuevas	EmmanuelAC	Mexico	No Participation
Marcel Bezdrighin	please_delete_account	Moldova	2014
Mihail Tarigradschi	ThatMathGuy	Moldova	No participation
Chihai Mihai	mihaiI	Moldova	No participation
Motroi Valeriu	fake_delete_account	Moldova	No participation
Dejan Todorovic	dejo	Montenegro	2014
Velibor Dosljak	nnMan	Montenegro	No Participation
Maciej Hołubowicz	znirzej	Poland	No Participation
Jarosław Kwiecień	yarek	Poland	2014
Przemysław Jakub Kozłowski		Poland	No Participation
Konrad Jan Paluszek		Poland	No Participation
Gonçalo Paredes	gonP	Portugal	2014
José Correia	jrcc	Portugal	No Participation
João Lago	joaolago	Portugal	No Participation
Fábio Colaço	fabioiuri	Portugal	No Participation
Hanpil Kang	Konijntje	Republic of Korea	No Participation
Jaehyun Koo	ko_osaga	Republic of Korea	No Participation
Jeehak Yoon	HYPERHYPERHYPERCUBELOVER	Republic of Korea	2014
Seunghyun Joe	ainta	Republic of Korea	2014
Alexandru Velea	alex.velea	Romania	2014
Rares Buhai	rares.buhai	Romania	2012 , 2013 , 2014
Andrei Popa	AndreiNet	Romania	No Participation
Valentin Harsan	valih10	Romania	No Participation
Mikhail Ipatov	LHiC	Russia	No participation
Vladislav Makeev	V--o_o--V	Russia	No participation
Mikhail Putilin	SpyCheese	Russia	No participation
Nikolay Budin	budalnik	Russia	No participation
Marko Stanković	MeinKraft	Serbia	2013 , 2014
Dimitrije Erdeljan	dd__	Serbia	2013 , 2014
Dušan Živanović	zDule98	Serbia	No Participation
Nikola Jovanović	randomusername	Serbia	No Participation
Teo Por Loong		Singapore	No Participation
Feng Jiahai		Singapore	2014
Pang Wen Yuen	pwypeanut	Singapore	No Participation
Howe Choong Yin		Singapore	No Participation
Eduard Batmendijn	Baklazan	Slovakia	2012 , 2013 , 2014
Bui Truc Lam		Slovakia	2014
Pavel Madaj		Slovakia	No Participation
Samuel Sládek	samo98	Slovakia	No Participation
David Wärn		Sweden	No Participation
Aleksandar Abas	Alex7	Syria	2014
Joud Zouzou	RedNextCentury	Syria	2014
Besher Massri	besher	Syria	No Participation
Mohammad Dwik	Bug	Syria	No Participation
Pochang Chen	johnchen902	Taiwan	2014
Po Jui Chen	a00012025	Taiwan	No Participation
Mekhrubon Turaev	Ximera	Tajikistan	2013,2014
Nodir Daminov	Nodir.Daminov	Tajikistan	No Participation
Doro Umarov	Alnair	Tajikistan	2013,2014
Suhaylii Bakhoduri	Suhaylee	Tajikistan	No Participation
Muhammed İkbal Kazar	ikbal	Turkey	No Participation
Muhammed Emin Ayar	EMINAYAR	Turkey	2014
Abdullah Enes ÖNCÜ	enesoncu	Turkey	2014
Kayacan Vesek	KayacanV	Turkey	No Participation
Bayram Berdiyev	bayram	Turkmenistan	2014
Silap Aliyev	accidentallygivenfuck	Turkmenistan	2013 2014
Allanur Shiriyev	Allanur	Turkmenistan	No Participation
Gunesh Purchekov		Turkmenistan	No Participation
Moakher Mohamed	moakhey	Tunisia	No Participation
Shevchenko Ilya	Scorpy	Ukraine	2013 2014
Aslandukov Matvey	BigBag	Ukraine	No Participation
Kachur Roman	Maestr0	Ukraine	No Participation
Mikhno Mark	AllCatsAreBeautiful	Ukraine	No Participation
Rowan Lee	Rowan.Lee	United Kingdom	No Participation
Daniel Chiu	waterfalls	USA	No Participation
Demi Guo	DemiGuo	USA	No Participation
Alexander Wei	yummy	USA	No Participation
Andrew He	ecnerwala	USA	2014
Andrew Li	ParanoidAndroid	Uzbekistan	No Participation
Raif Akhmedshin	RaifAkhmedshin	Uzbekistan	No Participation
Abdulla Axmadaliyev	a1549a	Uzbekistan	No Participation
Ulugbek Sobirov	BEK97	Uzbekistan	No Participation
Nguyen Tien Trung Kien	kien_coi_1997	Vietnam	2014
Pham Van Hanh	I_love_tigersugar	Vietnam	No Participation
Nguyen Viet Dung	toilanvd_HSGS	Vietnam	No Participation
Phan Duc Nhat Minh	minh141198	Vietnam	No Participation

Please feel free to post the participants here too, so that there will be something to discuss :)

Congratulations! To those who qualified for IOI 2015 :)

Hello everyone!

So, the problem is to find all prime numbers on segment N .. N+M where 10¹⁰ <= N <= 10¹¹ and 1 <= M <= 10⁵.

My algorithm with O(M * sqrt(K)) asymptotic, where K — is the number that we are testing for primality exceeds TL.