Trojke

#include <iostream>
#include <complex>
#include <vector>
#define X real()
#define Y imag()

using namespace std;

vector<complex<int> > v;

int main(){
    int n;
    cin >> n;

    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            char c;
            cin >> c;
            if(c != '.') v.push_back({i, j});
        }
    }

    int z = v.size();
    int t = 0;

    for(int i=0; i<z; i++){
        for(int j=i+1; j<z; j++){
            for(int k=j+1; k<z; k++){
                if((conj(v[i]-v[j])*(v[i]-v[k])).Y == 0) t++;
            }
        }
    }

    cout << t;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED