countTheTriplets.cpp

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

int main() {
	int testCases, arrayLength;
	cin>>testCases;
	for(int i = 0; i < testCases; i++) {
	    cin>>arrayLength;
	    int arr[arrayLength];
	    for(int j = 0; j < arrayLength; j++) {
	        cin>>arr[j];
	    }
	    sort(arr,arr+arrayLength);
	    int triplets = 0;
	    for(int j = arrayLength-1; j > 0; j--) {
    	    int pointer = 0 , right = j-1;
	        while(pointer < right) {
	            if((arr[right] + arr[pointer]) == arr[j]) {
	                triplets++;
	                right--;
	                pointer++;
	            }
	            else if ((arr[right] + arr[pointer]) < arr[j]) {
	                pointer++;
	            }
	            else {
	                right--;
	            }
	        }
	    }
	    if (triplets!=0) {
	        cout<<triplets<<"\n";
	    } else {
	        cout<<-1<<"\n";
	    }
	}

	return 0;
}