CodeForces - 597C Subsequences （树状数组+动态规划）

For the given sequence with n different elements find the number of increasing subsequences with k + 1elements. It is guaranteed that the answer is not greater than 8·10¹⁸.

Input

First line contain two integer values n and k (1 ≤ n ≤ 10⁵, 0 ≤ k ≤ 10) — the length of sequence and the number of elements in increasing subsequences.

Next n lines contains one integer a_i (1 ≤ a_i ≤ n) each — elements of sequence. All values a_i are different.

Output

Print one integer — the answer to the problem.

Examples

Input

5 2
1
2
3
5
4

Output

7

题意：
给定包含了 n 个不同元素的序列，找出含有 k + 1 个元素的递增子序列有多少个。数据保证：答案不超过 8·1018 。
思路：
dp[a[i]][k]表示以a[i]为结尾，长度为k的子序列的个数.

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转载于:https://www.cnblogs.com/ZGQblogs/p/10726742.html