spoj#KMEDIAL. Median of sub-sequences
Median of sub-sequences
Let a given sequence S (of length n) of positive integers be called x-medial (where x is a positive integer) if:
- n is odd, and the median of the sequence (the ((n+1)/2)th largest term) equals x. OR
- n is even, and both the central terms ( (n/2)th largest and (n/2+1)th largest) are equal to x.
Given a sequence A (of length N) of positive integers and an integer k, find out how many of its sub-sequences are k-medial.
A sub-sequence of A is any sequence {A[i], A[i+1], A[i+2]... , A[j]}, where 0 ≤ i ≤ j < N.
Input
The first line contains T (T≤15), the number of test cases.
Each test case consists of 2 lines. The first line contains the numbers N (1≤N≤105) and k (1≤k≤109), seperated by a single space.
The next line contains the sequence A (N terms, each ≤ 109, seperated by single spaces between them).
Output
Output T lines, each containing a single integer, equal to the number of k-medial sub-sequences.
Example
Input: 2
3 5
17 5 2
5 2
1 2 2 3 7
Output: 2
7