[Usaco2016 Jan]Subsequences Summing to Sevens

时间限制:10s      空间限制:128MB

题目描述

Farmer John's N cows are standing in a row, as they have a tendency to do from time to time. Each cow is labeled with a distinct integer ID number so FJ can tell them apart. FJ would like to take a photo of a contiguous group of cows but, due to a traumatic childhood incident involving the numbers 1…6, he only wants to take a picture of a group of cows if their IDs add up to a multiple of 7.
Please help FJ determine the size of the largest group he can photograph.
The first line of input contains N(1≤N≤50,000). The next N lines each contain the N integer IDs of the cows (all are in the range 0…1,000,000
).
给定长度为N的数列A,求A最长的连续子序列,满足子序列中元素的和是7的倍数。输出最大的长度。如果不存在满
足条件的子序列,输出0。1 ≤ N ≤ 50000, 0 ≤ A_i ≤ 10 ^ 6


输入格式

Please output the number of cows in the largest consecutive group whose IDs sum to a multiple of 7. If no such group exists, output 0.


输出格式

You may want to note that the sum of the IDs of a large group of cows might be too large to fit into a standard 32-bit integer. If you are summing up large groups of IDs, you may therefore want to use a larger integer data type, like a 64-bit "long long" in C/C++.


样例输入

7
3
5
1
6
2
14
10

样例输出

5

In this example, 5+1+6+2+14 = 28. 

提示

没有写明提示


题目来源

Silver 鸣谢frank_c1提供翻译