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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] ≤ 107). 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
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 |
hide comments
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2015-11-02 20:37:04
superb use of divide and conquer ;) |
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2015-10-20 22:49:41 Advitiya
YODANESS~INVCNT :) mergesort |
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2015-10-19 10:53:37
how unsorted the array is!!! :) |
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2015-10-15 13:31:48 Mateusz Kwasniak
Of course both div&conq and BIT will work. Good one. Last edit: 2015-10-15 13:32:09 |
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2015-10-14 06:01:18
datatype of count to be noted (long long int), caused me 2 WA! |
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2015-09-23 21:14:33 Sarthak Munshi
2 WA, 2 RE , 1 CE . But then AC using BIT ! |
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2015-09-18 23:45:58 Nitin Tiwari
accepted in first go |
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2015-09-15 15:01:38 MSK
solved using bit... awesome feeling.... :) |
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2015-09-05 19:00:39 thirupathireddy
long long int .....................:) leads to wrong answer......... |
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2015-09-03 19:15:18 codeprince
@pvsmpraveen... 5 is number of elements that shouldn't be considered |