Finding Pairs

3.4

36 votes
Algorithms, Medium, Sorting
Problem

Given an array A of N numbers, find the number of distinct pairs (i, j) such that j >=i and A[i] = A[j].

First line of the input contains number of test cases T. Each test case has two lines, first line is the number N, followed by a line consisting of N integers which are the elements of array A.

For each test case print the number of distinct pairs.

Constraints
1 <= T <= 10
1 <= N <= 10^6
-10^6 <= A[i] <= 10^6 for 0 <= i < N

Time Limit: 3
Memory Limit: 256
Source Limit:
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