背景

^_^

题目描述

Farmer John has noticed that the quality of milk given by his cows varies from day to day. On further investigation, he discovered that although he can't predict the quality of milk from one day to the next, there are some regular patterns in the daily milk quality.

To perform a rigorous study, he has invented a complex classification scheme by which each milk sample is recorded as an integer between 0 and 1,000,000 inclusive, and has recorded data from a single cow over N (1 ≤ N ≤ 20,000) days. He wishes to find the longest pattern of samples which repeats identically at least K (2 ≤ K ≤ N ) times. This may include overlapping patterns -- 1 2 3 2 3 2 3 1 repeats 2 3 2 3 twice, for example.

Help Farmer John by finding the longest repeating subsequence in the sequence of samples. It is guaranteed that at least one subsequence is repeated at least K times.

格式

输入

Line 1: Two space-separated integers: N and K

Lines 2.. N +1: N integers, one per line, the quality of the milk on day i appears on the ith line.

输出

Line 1: One integer, the length of the longest pattern which occurs at least K times.

样例

8 2
1
2
3
2
3
2
3
1

4

测试限制

每个测试点均为 2s, 64MiB .

一句话题意：

给出一个数列，求出数列中最长连续子序列的长度，并且满足该子序列在数列中出现超过k次。

其中10%的测试点：$a_i$ 全部相等，$1 \leq N \leq 2 \times 10^4$;

另外10%的测试点：$1 \leq N \leq 10 , k = 2$;

另外40%的测试点：$1 \leq N \leq 100，2 \leq K \leq 10$；

100%数据： $ 1 \leq N \leq 2 \times 10^4， 2 \leq K \leq N, 0 \leq a_i \leq 1 \times 10^6。 $

source

milk patterns-POJ