# DCP-422: Double Pairs Back to All Problems

Medium Data Structures > Binary Indexed Tree

You are given an array A of length N. Your task is to find out count of total pairs of indices , say i and j, such that: 1. i<j 2. A[i]*2 <=A[j] Input: ------ Input starts with an integer **T (1<=T<=10)**, denoting the number of test cases. Each case contains an integer **N (1 ≤ N ≤ 100000)** denoting the number of elements of array **A**. The next line will contain **N** integers separated by spaces, denoting the elements of the array **A**. Each of these integers will be non-negative integer not greater than **10^18**. Output: ------- For each case of input, output the total numbers of pairs. Sample Input ------------ 1 3 1 2 5 Sample Output ------------- 3

### Problem Limits

 Language Time Limit (seconds) C 4.00 C++ 4.00 C++14 4.00 C# 6.00 Go 6.00 Java 6.00 JavaScript 6.00 Objective-C 6.00 Perl 6.00 PHP 6.00 Python 6.00 Python3 6.00 Ruby 6.00 VB.Net 6.00

# 55/344

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