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题解：有点像找逆序对，因为子串的长度有限制，所以对于每一个s[i]，当它作为尾部时，头部的范围是(i-R+1,i-L+1)；当它作为头部时，尾部的范围是(i+L-1,i+R-1)。修改的时候先减掉该位置原来的数的贡献。 阅读全文
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A-百度无人车 题解：典型的二分 B-百度科学家 题解：数据比较小的时候建图，跑DFS统计总的污染值即可。 感受：题意不明！！！！！书替换后不会对以前的结果造成影响。所以~~要n何用。 阅读全文
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题解：贪心，先处理人数多的组，把符合条件(能装下整个队伍的地点)的丢到优先队列里（保证没有遗漏可能的解）。然后遍历每个组时取队列里的最小值就可以了。 阅读全文
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Polycarp is a beginner programmer. He is studying how to use a command line. Polycarp faced the following problem. There are n files in a directory an 阅读全文
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A group of n friends enjoys playing popular video game Toda 2. There is a rating system describing skill level of each player, initially the rating of 阅读全文
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A. Links and Pearls 题解：~~~没啥说的，没有pearls也算YES！！！ B. Marlin 题解：k是偶数，好办。k是奇数，分类讨论，如果k<=n-2，放在中间。如果k>n-2，第三排第1个位置和第n-2个位置放上‘#’（0到n-1）。至于为啥子，拿笔画一下就明白了。 C. 阅读全文
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You are given an integer array of length nn. You have to choose some subsequence of this array of maximum length such that this subsequence forms a in 阅读全文
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Polycarp likes to play with numbers. He takes some integer number xx, writes it down on the board, and then performs with it n−1n−1 operations of the 阅读全文
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You are given an undirected graph consisting of nn vertices and mm edges. Your task is to find the number of connected components which are cycles. He 阅读全文
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After a long series of jobless days, Sherlock and Watson frustated by the lack of new cases, decide to turn their minds toward something interesting l 阅读全文