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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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2015-05-18 14:48:01 i_am_looser
Done it using segment tree.... |
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2015-05-17 08:08:19 :.Mohib.:
Binary tree ==> AC :) |
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2015-05-14 18:14:45 Prismatic
Easy using BIT |
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2015-05-07 14:54:24 Cr
don't forget result is long long type |
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2015-04-23 08:59:30 Phong
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!! |
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2015-04-15 07:07:57 Tony T.
Wrote something quick to generate test cases: <snip> Last edit: 2022-06-26 16:04:52 |
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2015-04-14 06:54:06 Tony T.
I had a pointer problem, else merge sort works great. Was just getting into BIT.. thought it was pretty complicated. Last edit: 2015-04-15 07:08:46 |
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2015-04-01 19:39:38 Madhav
nope Last edit: 2015-04-02 03:06:11 |
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2015-03-27 02:09:15 abvj
nope Last edit: 2015-04-02 03:06:26 |
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2015-03-23 00:43:53 soshika
cool :B |