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
Cr:
20150507 14:54:24
don't forget result is long long type 

Phong:
20150423 08:59:30
Why is my code getting WA? I tried to submit it on vn.spoj.com with a similar problem and the exact code and it got AC. Confused!! 

Tony T.:
20150415 07:07:57
Wrote something quick to generate test cases: https://ideone.com/2FQM4J 

Tony T.:
20150414 06:54:06
I had a pointer problem, else merge sort works great.


Madhav:
20150401 19:39:38
nope Last edit: 20150402 03:06:11 

abvj:
20150327 02:09:15
nope


soshika:
20150323 00:43:53
cool :B 

Fufo:
20150126 13:48:05
Last edit: 20150126 13:48:30 

internom:
20150126 13:15:50
Last edit: 20150126 13:16:19 

Rajat (1307086):
20150118 19:49:38
Divide and Conquer. 
Added by:  Paranoid Android 
Date:  20100306 
Time limit:  3.599s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: PERL6 