When Elita’s best friend, Carmella, disappears under mysterious circumstances. Elita feels driven to find her. She’s convinced the puzzle Carmella was working on the day she disappeared is somehow involved. She takes the puzzle and puts it together herself—and suddenly finds herself pulled into Puzzle Land. Elita is confronted by a strange and sinister man named Professor Robinson, an evil wizard who cast a spell on puzzles. In the beginning, he wanted to create a special place for the homeless children of the world, but his greed took hold. The professor began to kidnap any child he could. Soon, Andy and Aaron follow Elita and Carmella into the puzzle. As they travel through Puzzle Land, their bodies begin to take on the shape of a new creature. It is only after they learn to forgive one another, to be honest, and to work as a team that they find the strength to escape Professor Robinson and his puzzle world.

Algorithmic puzzles are puzzles involving well-defined procedures for solving problems. This book will provide an enjoyable and accessible introduction to algorithmic puzzles that will develop the reader's algorithmic thinking. The first part of this book is a tutorial on algorithm design strategies and analysis techniques. Algorithm design strategies — exhaustive search, backtracking, divide-and-conquer and a few others — are general approaches to designing step-by-step instructions for solving problems. Analysis techniques are methods for investigating such procedures to answer questions about the ultimate result of the procedure or how many steps are executed before the procedure stops. The discussion is an elementary level, with puzzle examples, and requires neither programming nor mathematics beyond a secondary school level. Thus, the tutorial provides a gentle and entertaining introduction to main ideas in high-level algorithmic problem solving. The second and main part of the book contains 150 puzzles, from centuries-old classics to newcomers often asked during job interviews at computing, engineering, and financial companies. The puzzles are divided into three groups by their difficulty levels. The first fifty puzzles in the Easier Puzzles section require only middle school mathematics. The sixty puzzle of average difficulty and forty harder puzzles require just high school mathematics plus a few topics such as binary numbers and simple recurrences, which are reviewed in the tutorial. All the puzzles are provided with hints, detailed solutions, and brief comments. The comments deal with the puzzle origins and design or analysis techniques used in the solution. The book should be of interest to puzzle lovers, students and teachers of algorithm courses, and persons expecting to be given puzzles during job interviews.

This book constitutes the refereed proceedings of the 9th International Workshop on Groupware, CRIWG 2004, held in San Carlos, Costa Rice in September 2004. The 16 revised full papers and 13 revised short papers presented together with a keynote paper were carefully reviewed and selected from 71 submissions. The papers are organized in topical sections on knowledge management, awareness, support for collaborative processes, collaborative applications, groupware infrastructure, computer supported collaborative learning, and collaborative mobile work.

Includes tutorials, lectures, and refereed papers on all aspects of logic programming, including theoretical foundations, constraints, concurrency and parallelism, deductive databases, language design and implementation, nonmonotonic reasoning, and logic programming and the Internet. The International Conference on Logic Programming, sponsored by the Association for Logic Programming, includes tutorials, lectures, and refereed papers on all aspects of logic programming, including theoretical foundations, constraints, concurrency and parallelism, deductive databases, language design and implementation, nonmonotonic reasoning, and logic programming and the Internet.

Return to Puzzle Land is a sequel to the Magic Puzzle. The evil wizard Professor Robinson has put a spell on select puzzles, for the purpose of kidnapping children and making them serve him. When Carmella, Elita, Andy, and Aaron attempt to put a puzzle together, they are zapped into a new world called Puzzle Land. Here, Professor Robinson transforms them into creatures with special abilities. After escaping Puzzle Land, the four children attempt to put their whole scary adventure behind them, but their time in Puzzle Land is not over yet! Aaron is having dreams that the mermaids who helped save them are in trouble. Elita knows they must rescue the other children who were left in Puzzle Land! Nightmares of Professor Robinson still torment them. Will they dare to enter Puzzle Land a second time and rescue the lost children? Will they be able to overcome the tempting choices they must make to put an end to this villain once and for all? Find out as you dare to join our hero’s as they return to Puzzle Land!

Galen’s life will never be the same again. What he thought would be a leisurely voyage on a ship will now become the most challenging experience he’s ever had. Together with his brother and friends, they must save the Items of Chaos before an evil force unleashes them and destroys the world. The problem is, will they be able to do it?