#include <bits/stdc++.h>
using namespace std;

int main() 
{
   // cout << "Hello, World!";
   int t;cin>>t;
   while(t--)
   {
     long long  int n;cin>>n;
      long long arr[n];
      long long sum=0;
      long long temp=0;
      
      for(int i=0;i<n;i++)
      {
        cin>>arr[i];
        sum=sum+arr[i];
      }
      temp=sum%n;
      sum=(sum/n);
     // cout<<temp<<endl;
    // cout<<sum<<endl;
      long long a=sum*2;
      long long b=sum*2+temp;
      sort(arr, arr+n);
    long long ans=0;
      for(int i=0;i<n;i++)
      {  
         
         long long c=a-arr[i];
         long long d=b-arr[i];
         auto it=lower_bound(arr+i+1, arr+n ,c );
         auto it2=upper_bound(arr+i+1, arr+n, c);
         it2--;
         if(*it==c)
         {
            ans=ans+it2-it+1;
         }
         if(a!=b){
         auto it3=upper_bound(arr+i+1, arr+n ,c);
         auto it4=upper_bound(arr+i+1, arr+n ,d);
         it4--;
         if((*it3)>c && (*it3)<=d)
         {
           ans=ans+it4-it3+1; 
         }
         }
      }
      cout<<ans<<"\n";
   }
    return 0;
}
by

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}