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
offamitkumar:
20200329 10:47:02
Solved it With


vishesh_2308:
20200312 10:57:36
https://youtu.be/B29dVmpIpn0


terminator_pk:
20200207 19:18:21
Last edit: 20200208 12:55:30 

savage_19:
20200204 08:30:10
1. Do it with merge sort first.


avsd_47:
20200121 18:22:23
Caution:the answer you are going to print must be of type long long costed me 3 wa's. 

sangmai:
20200117 03:14:50
AC in one go using merge sort 

sajalagrawal14:
20191203 13:46:03
Can be solved Using


codefresher:
20191122 22:44:54
Good one....solved using merge sort tree...segment tree??? 

abhishak69:
20191122 21:51:35
my first fenwick tree question :) 

ishancosmos25:
20191110 05:27:54
Used BIT and inversions count to solve the problem.

Added by:  Paranoid Android 
Date:  20100306 
Time limit:  3.599s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: PERL6 