Difference between revisions of "XVIII Open Cup named after E.V. Pankratiev. Grand Prix of Ukraine"
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Xiejiadong (talk | contribs) (Created page with "== Problem A == Unsolved. == Problem B == Solved by Weaver_zhu. 0:21 (+) == Problem C == Solved by Xiejiadong && Kilo_5723. 2:56 (+) == Problem D == Solved by Kilo_5723...") |
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Solved by Xiejiadong && Kilo_5723. 2:56 (+) | Solved by Xiejiadong && Kilo_5723. 2:56 (+) | ||
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+ | 题意:求一个价值最大的子序列,一个子序列的价值是 $\frac{len_t^2}{c_t}$ , $len_t^2$ 表示子序列的长度, $c_t$ 表示子序列的循环节长度。 | ||
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+ | 题解:因为只有三种子母,所以必有其中一种子母的数量 $\ge \frac{n}{3}$ ,对于所有这种子母组成的组序列,他的价值 $\ge \frac{len^2}{9}$ ,所以我们只需要枚举分母 $\le 8$ 的。 | ||
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+ | 显然分母 $\le 8$ 的不多,对于确定的循环节,枚举满足要求的最长子序列即可,枚举子序列的复杂度是 $O(n)$ 的。 | ||
== Problem D == | == Problem D == |
Revision as of 12:45, 29 May 2019
Problem A
Unsolved.
Problem B
Solved by Weaver_zhu. 0:21 (+)
Problem C
Solved by Xiejiadong && Kilo_5723. 2:56 (+)
题意:求一个价值最大的子序列,一个子序列的价值是 $\frac{len_t^2}{c_t}$ , $len_t^2$ 表示子序列的长度, $c_t$ 表示子序列的循环节长度。
题解:因为只有三种子母,所以必有其中一种子母的数量 $\ge \frac{n}{3}$ ,对于所有这种子母组成的组序列,他的价值 $\ge \frac{len^2}{9}$ ,所以我们只需要枚举分母 $\le 8$ 的。
显然分母 $\le 8$ 的不多,对于确定的循环节,枚举满足要求的最长子序列即可,枚举子序列的复杂度是 $O(n)$ 的。
Problem D
Solved by Kilo_5723. 0:39(+)
Problem E
Unsolved.
Problem F
Solved by Xiejiadong. 0:57 (+)
Problem G
Unsolved. (-1)
Problem H
Solved by Kilo_5723. 1:33 (+1)
Problem I
Unsolved.
Problem J
Unsolved. (-17)
Problem K
Unsolved.
Problem L
Solved by Weaver_zhu. 2:03 (+)