INVCNT - Inversion Count


Let A[0...n - 1] be an array of n distinct positive integers. If i < j and A[i] > A[j] then the pair (i, j) is called an inversion of A. Given n and an array A your task is to find the number of inversions of A.

Input

The first line contains t, the number of testcases followed by a blank space. Each of the t tests start with a number n (n <= 200000). Then n + 1 lines follow. In the ith line a number A[i - 1] is given (A[i - 1] <= 10^7). The (n + 1)th line is a blank space.

Output

For every test output one line giving the number of inversions of A.

Example

Input:
2

3
3
1
2

5
2
3
8
6
1


Output:
2
5

hide comments
gabrijel: 2019-03-27 23:41:09

Yes, output can be up to n^2 so O(n^2) should definitely pass.

fabijanb: 2019-03-27 21:50:29

original problem, I know how to solve it, is O(n ^ 2) okay?

linkret: 2019-03-27 16:12:41

not bad task...

kcluez: 2019-03-23 12:00:43

use long long to store the count of inversions because the number of inversions in the worst case can be n^2 when the array is reverse sorted.Got 2 WA due to this mistake. finally solved.

ab_biswas09: 2019-03-07 13:47:32

SOLVED using BIT in one go

masterchef2209: 2019-03-06 15:55:46

solved this problem after months. really good question

dkkv0000: 2019-01-20 19:49:52

@marethyu thank u

iamjacksparrow: 2019-01-18 23:37:10

used bit to solve

striver_79: 2019-01-17 09:09:39

Try solving https://codeforces.com/problemset/problem/459/D after you solve this.

marethyu1: 2019-01-01 20:58:36

Use long long when counting inversions, it cost me several WAs!


Added by:Paranoid Android
Date:2010-03-06
Time limit:3.599s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: PERL6