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
hide comments
jmr99:
2018-03-16 19:57:39
how to solve this using #graph-theory #number-theory #shortest-path pls somebody share the idea . |
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mranderson:
2018-03-16 19:52:03
use long long int for the count |
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jmr99:
2018-03-16 16:24:21
Last edit: 2018-03-16 19:52:08 |
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jmr99:
2018-03-16 12:15:54
hint : : use BIT or Merge
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kkislay20:
2018-03-16 12:01:15
I'm getting WA!!! Somebody please help.
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ash_maurya:
2018-03-16 07:15:19
@addy1397 There are n distinct numbers in the problem, none of them are repeated. Some of your random inputs are invalid.
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zephyr_96:
2018-02-26 22:01:11
Use BigInteger (number of inversions) for java else you will get WA. Last edit: 2018-02-26 22:02:24 |
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saurabh987:
2018-01-14 14:14:47
my 100th :) using BIT |
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ultra_7:
2017-12-31 17:32:15
Make sure to use long long in c++ |
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sagarthecoder:
2017-12-28 11:14:17
I used segment tree.
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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 |