# How to prepare for ACM – ICPC?

ACM ICPC(Association for Computing Machinery – International Collegiate Programming Contest) is a world-wide annual multi-tiered programming contest being organized for over thirteen years. The contest is sponsored by IBM.

This article focuses on what all topics that are important for the competitive programming and should especially be studied in order to train yourself for upcoming ACM-ICPC contest.

Rules of the Contest – World final Rules for 2017 Click here

Indian Participants – Codechef conducts all the Indian Regionals. Click here to know about team formation, reimbursements etc

ICPC for Schools by CodeChef – This competition serves as a gateway for the school students to participate in ACM ICPC contest along with ICPC college participants held across India. It is an idea conceived by CodeChef and supported by Amrita University.

A sample ICPC Problem : A usual ICPC problem has the following features:

1. Problem statement: describing the problem and what output is to be generated.
2. Input: Make sure that you read this section with complete attention as missing out any minor detail may land you in wrong answer zone.
3. Output: Just like above, this one also should be read carefully.
4. Constraints: These can include constraints on input, time, memory, code size, etc.
5. Time limit: See if your algorithm can work in this range. If not, time to change it!
6. Memory limit: If you are fond of allocating memory for every small thing, it’s a good time that you changed it.

Preparing for ACM-ICPC

First and foremost Step: PRACTICE – Following are the resources that can be referred for practicing the ACM-ICPC alike contests and problems. For all these OJs, begin with the problems with maximum submissions and check other solutions to check how you may improve. Do Participate in their monthly contests to remain up to the mark.

• ACM-ICPC Past Problems – ICPC Archive, Practice at Codechef
• TopCoder – Proceed by increasing problem levels gradually
• Codeforces -List of Problem Sets
• Codechef – Beginers can start with Codechef Beginners and proceed further
• SPOJ – Move from easy to tough problems
• USACO – Excellent training resource
• uvaOnline Judge – Huge repositry of problems
• Hackerrank – Practice problems topic wise and participate in preparatory series
• Hackerearth – Participate in preparatory series
• Practice – Good for beginners. Has problems ranging from difficulty level School to Hard.
• List of various Competitive Programming Contests available online all through the year

What to study?

Knowing just the basics of programming won’t be fruitful for aspirants of ACM ICPC. One needs to have a thorough knowledge of advanced algorithms used as well. Following Topics list out the necessary Topics and Algorithms that one must surely know to improve and stand a chance in the actual competition.

Elementary data structures: To begin with competitive programming, one must master the Data Structures. Following is the list of most commonly used data structures:

Priority queues, union-find sets, (augmented) interval trees, (augmented) balanced BSTs and binary indexed trees

Sorting and Searching : Concentrate to learn the basic concepts and also get familiar with all the library functions available.

String manipulation : Strings make programming problems interesting and difficult too and probably thats the reason they are used extensively in such contests. Learning library functions for String actually proves very helpful (C++ : See this and this, String in Java).

Choosing the right Language : C++ is till date most preferred language followed by Java when it comes to programming contests but you should always choose a language you are comfortable with. Being CONFIDENT in any language is most important.

Standard Template Library : A quintessential especially for those using C++ as a language for coding

Dynamic Programming

All DP Algorithms

BackTracking

More articles on Backtracking

Greedy Algorithms

More articles on Greedy Algorithms

Graph Algorithms : One of the most important topic which you can not ignore if preparing for ACM – ICPC.

All Graph Algorithms

Basic Mathematics

Arithmetic : Programmers must know how integers and real numbers are represented internally and should be able to code high-precision numbers. Bit manipulation tricks and knowing library functions for number basic arithmetic would be very helpful.

Number theory : Knowing some of these concepts would save a lot of time and efforts while programming in the contests.

Combinatorics : Although directly might not seam to be important, Combinatorics is important to estimate asymptotic complexity of algorithms.

Geometrical Algorithms

Network Flow Algorithms

All Articles on Geometric Algorithms