A11036. Two Melodies
编程题
普及/提高-
知识点
题目描述
Alice is a beginner composer and now she is ready to create another masterpiece. And not even the single one but two at the same time!
Alice has a sheet with $n$ notes written on it. She wants to take two such non-empty non-intersecting subsequences that both of them form a melody and sum of their lengths is maximal.
Subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements.
Subsequence forms a melody when each two adjacent notes either differs by 1 or are congruent modulo 7.
You should write a program which will calculate maximum sum of lengths of such two non-empty non-intersecting subsequences that both of them form a melody.
Alice has a sheet with $n$ notes written on it. She wants to take two such non-empty non-intersecting subsequences that both of them form a melody and sum of their lengths is maximal.
Subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements.
Subsequence forms a melody when each two adjacent notes either differs by 1 or are congruent modulo 7.
You should write a program which will calculate maximum sum of lengths of such two non-empty non-intersecting subsequences that both of them form a melody.
输入格式
The first line contains one integer number $n$ ( $2<=n<=5000$ ).
The second line contains $n$ integer numbers $a_{1},a_{2},...,a_{n}$ ( $1<=a_{i}<=10^{5}$ ) — notes written on a sheet.
The second line contains $n$ integer numbers $a_{1},a_{2},...,a_{n}$ ( $1<=a_{i}<=10^{5}$ ) — notes written on a sheet.
输出格式
Print maximum sum of lengths of such two non-empty non-intersecting subsequences that both of them form a melody.
输入输出样例
输入 #1
4 1 2 4 5
输出 #1
4
输入 #2
6 62 22 60 61 48 49
输出 #2
5
说明/提示
In the first example subsequences $[1,2]$ and $[4,5]$ give length 4 in total.
In the second example subsequences $[62,48,49]$ and $[60,61]$ give length 5 in total. If you choose subsequence $[62,61]$ in the first place then the second melody will have maximum length 2, that gives the result of 4, which is not maximal.
In the second example subsequences $[62,48,49]$ and $[60,61]$ give length 5 in total. If you choose subsequence $[62,61]$ in the first place then the second melody will have maximum length 2, that gives the result of 4, which is not maximal.