Codeforces Round 384 (Div. 2)
E
Vladik and cards
Codeforces
2200
原题
← D→
翻译中…

Vladik was bored on his way home and decided to play the following game. He took $*n*$ cards and put them in a row in front of himself. Every card has a positive integer number not exceeding $8$ written on it. He decided to find the longest subsequence of cards which satisfies the following conditions:

翻译中…
  • the number of occurrences of each number from $1$ to $8$ in the subsequence doesn't differ by more then $1$ from the number of occurrences of any other number. Formally, if there are $*c*_{*k*}$ cards with number $*k*$ on them in the subsequence, than for all pairs of integers image the condition $|*c*_{*i*} - *c*_{*j*}| ≤ 1$ must hold.
  • if there is at least one card with number $*x*$ on it in the subsequence, then all cards with number $*x*$ in this subsequence must form a continuous segment in it (but not necessarily a continuous segment in the original sequence). For example, the subsequence $[1, 1, 2, 2]$ satisfies this condition while the subsequence $[1, 2, 2, 1]$ doesn't. Note that $[1, 1, 2, 2]$ doesn't satisfy the first condition.
翻译中…

Please help Vladik to find the length of the longest subsequence that satisfies both conditions.

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Input

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The first line contains single integer $*n*$ ($1 ≤ *n* ≤ 1000$) — the number of cards in Vladik's sequence.

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The second line contains the sequence of $*n*$ positive integers not exceeding $8$ — the description of Vladik's sequence.

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Output

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Print single integer — the length of the longest subsequence of Vladik's sequence that satisfies both conditions.

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Note

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In the first sample all the numbers written on the cards are equal, so you can't take more than one card, otherwise you'll violate the first condition.

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样例

Input #1
3
1 1 1
Output #1
1
InputCopy OutputCopy
Input #2
8
8 7 6 5 4 3 2 1
Output #2
8
InputCopy OutputCopy
Input #3
24
1 8 1 2 8 2 3 8 3 4 8 4 5 8 5 6 8 6 7 8 7 8 8 8
Output #3
17
InputCopy OutputCopy
题目信息
题号
743E
时间限制
2 s
内存限制
256 MB
标签
二分
位运算
暴力
动态规划

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。