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VirusWe have a log file, which is a sequence of recorded events. Naturally, the timestamps are strictly increasing.However, it is infected by a virus... 阅读全文
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Updating a DictionaryIn this problem, a dictionary is collection of key-value pairs, where keys are lower-case letters, and values are non-negative i... 阅读全文
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Robot InstructionsYou have a robot standing on the origin of x axis. The robot will be given some instructions. Your task is to predict its position ... 阅读全文
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Three FamiliesThree families share a garden. They usually clean the garden together at the end of each week, but last week, family C was on holiday, ... 阅读全文