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D. Equal Binary Subsequences Everool has a binary string $s$ of length $2n$. Note that a binary string is a string consisting of only characters $0$ a 阅读全文
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C1. Good Subarrays (Easy Version) This is the easy version of this problem. In this version, we do not have queries. Note that we have multiple test c 阅读全文
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B. Playing with GCD You are given an integer array $a$ of length $n$. Does there exist an array $b$ consisting of $n+1$ positive integers such that $a 阅读全文