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The Worm Turns Problem Description Winston the Worm just woke up in a fresh rectangular patch of earth. The rectangular patch is divided into cells, a 阅读全文
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Equations Problem Description Consider equations having the following form: a*x1^2+b*x2^2+c*x3^2+d*x4^2=0a, b, c, d are integers from the interval [-5 阅读全文
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Snail’s trouble Problem Description Once upon a time, there was a poor snail. Every day, it tried very hard to crawl forward, while there was a keeper 阅读全文