101 Programming Puzzle Problems Solved: Join us to win Informatics Olympiad

We are all aware of Olympiad contests in Chemistry, Mathematics, Biology, etc., but very few of us know about International Olympiad in Informatics (IOI). The idea of initiating international Olympiads in informatics for school students was proposed to the 24th General Conference of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in Paris by the Bulgarian delegate Professor Blagovest Sendov in October 1987. This plan was included into the Fifth Main Program of UNESCO for the biennium 1988-1989 (Section 05 215). In May 1989, UNESCO initiated and sponsored the first International Olympiad in Informatics (IOI). (Quoted from the IOI'89 and IOI'92 Report). The first IOI was held in Bulgaria in 1989. The IOI is one of five international science Olympiads. The primary goal of the IOI is to stimulate interest in informatics (computing science) and information technology. Another important goal is to bring together exceptionally talented pupils from various countries and to have them share scientific and cultural experiences. The IOI is organized annually in and by one of the participating countries. Each participating country typically sends a delegation of four contestants and two accompanying adults. Students compete individually and try to maximize their score by solving a set of informatics problems during two competition days. The competition tasks are of algorithmic nature; however, the contestants have to show such basic IT skills as problem analysis, design of algorithms and data structures, programming and testing. The winners of the IOI belong to the best young computer scientists in the world. The International Scientific Committee is responsible for a scientific content of the IOI and supervises the IOI. According to IOI records, India is participating in this grand even since 2002. Only in 2014, India has won one gold medal. Till now India has not hosted any IOI international finals event. Indian Computing Olympiad (ICO) is used to select the team of four students to represent India at IOI. This ICO is organized in two levels: Zonal Informatics Olympiad( ZIC) and Indian National Olympiad in Informatics (INOI). Students can also appear Zonal Computing Olympiad (ZCO) in online to qualify for INOI. In INOI, students are expected to solve given problems in C, C++, Java or Pascal. This book encompasses 101 selected questions that are asked in various programming contests organized for high school level students to orient them to IOI. Some of the selected examples are from past IOI with some being asked at regional level. We have supplied solutions along with explanations including program’s working snap shots. Some of the questions are from International Collegiate Programming Contest (ICPC) which is organized by Association of Computing Machinery (ACM) and IBM. The solutions which we have supplied are accepted by Sphere Online Judge (SPOJ) system at www.spoj.com. Also, some other questions solutions are accepted by www.wcipeg.com system. The solutions are given in C programming language. We presume that the reader has exposure to C programming language elements. For those people who feel that they only know the language and don’t yet developed their logic develop, we advise them to read the C programming books given in list of references. All the solutions are tested and developed under Bloodshed (www.bloodshed.net) Dev C++ integrated development environment (IDE) which uses GCC compiler tool chain. Selected 101 questions are presented in simple to difficult for progressive learning by the reader. About 50 percent of the selected questions need to use adhoc logic instead of structured concepts like queues, trees, stacks, etc. We have included enough explanation to make readers to understand the adhoc logic which we have employed in solving some of the problems. We have included figures wherever needed to explain the logic which we have employed in solving the problems.