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To prepare for PAT, the judge sometimes has to generate random passwords for the users. The problem is that there are always some confusing passwords 阅读全文
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A number that will be the same when it is written forwards or backwards is known as a Palindromic Number. For example, 1234321 is a palindromic number 阅读全文
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Two integers are called "friend numbers" if they share the same sum of their digits, and the sum is their "friend ID". For example, 123 and 51 are fri 阅读全文
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I went from zero, to my own hero. 阅读全文