Vladik and cards

# 翻译： 题意：给定序列A，A中均元素为$[1,8]$中的整数，求一个A的最长子序列且满足以下2个条件， 1. $[1,8]$中每2个整数的出现次数之差不超过1 2. 每种数字的全部元素必须连续， 即222333是合法的，223322不合法 n<=1000,(2s)

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

The first line contains single integer $ n $ ( $ 1<=n<=1000 $ ) — the number of cards in Vladik's sequence. The second line contains the sequence of $ n $ positive integers not exceeding $ 8 $ — the description of Vladik's sequence.

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

3
1 1 1

1

8
8 7 6 5 4 3 2 1

8

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

17

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.