diff --git a/luku01.tex b/luku01.tex
index 8e4f63a..9d95555 100644
--- a/luku01.tex
+++ b/luku01.tex
@@ -842,3 +842,83 @@ For example, the representation of
 $123$ in base $2$ is 1111011 and
 $\lfloor \log_2(123)+1 \rfloor = 7$.
 
+\section{Contests}
+
+\subsubsection{IOI}
+
+The International Olympiad in Informatics (IOI) \cite{ioi}
+is an annual programming contests for
+secondary school students.
+Each country is allowed to send a team of
+four students to the contest.
+There are usually about 300 participants
+from 80 countries \cite{iois}.
+
+The IOI consists of two five-hour long contests.
+In both contests, the participants are asked to
+solve three algorithm tasks of various difficulty.
+The tasks are divided into subtasks,
+each of which has an assigned score.
+Even if the contestants are divided into teams,
+they compete as individuals.
+
+The IOI syllabus \cite{ioiy} regulates the topics
+that may appear in IOI tasks.
+This book covers almost all topics in the IOI syllabus.
+
+The participants for the IOI are selected through
+national contests.
+Before the IOI, many regional contests are organized,
+such as the Baltic Olympiad in Informatics (BOI),
+the Central European Olympiad in Informatics (CEOI)
+and the Asia-Pacific Informatics Olympiad (APIO).
+
+Some countries organize online practice contests
+for future IOI participants,
+such as the Croatian Open Competition in Informatics (COCI) \cite{coci}
+and the USA Computing Olympiad (USACO) \cite{usaco}.
+
+\subsubsection{ICPC}
+
+The International Collegiate Programming Contest (ICPC) \cite{icpc}
+is an annual programming contest for university students.
+Each team in the contest consists of three students,
+and unlike in the IOI, the students work together;
+there is even only one computer available for each team.
+
+The ICPC consists of several stages, and finally the
+best teams are invited to the World Finals.
+While there are tens of thousands of participants
+in the contest, there are only 128 final slots available,
+so even advancing to the finals
+is a great achievement in some regions.
+
+In each ICPC contest, the teams have five hours time to solve
+about ten algorithm problems.
+A solution to a problem is accepted only if it solves
+all test cases efficiently.
+During the contest, the teams see the results of the other teams,
+but for the last hour the scoreboard is frozen and it
+is not possible to see the results of the last submissions.
+
+The topics that may appear at the ICPC are not so well
+specified as those at the IOI.
+In any case, it is clear that more knowledge is needed
+at the ICPC, especially more mathematical skills.
+
+\subsubsection{Online contests}
+
+There are also many online contests that are open for everybody.
+At the moment, the most active contest site is Codeforces
+that organizes contests about weekly.
+In Codeforces, participants are divided into two divisions:
+beginners compete in Div2 and more experienced programmers in Div1.
+Other contest sites include AtCoder, CS Academy, HackerRank and Topcoder.
+
+Some companies organize online contests with onsite finals.
+Examples of such contests are Facebook Hacker Cup,
+Google Code Jam and Yandex.Algorithm.
+Of course, companies also use those contests for recruiting:
+performing well in a contest is a good way to prove one's skills.
+
+\section{Resources}
\ No newline at end of file