Maraton

#include <bits/stdc++.h>

using namespace std;

int main(){

    vector<complex<int> > v[27];

    int n;
    cin >> n;

    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            char c;
            cin >> c;
            if(c=='.') continue;
            else v[c-65].push_back({i, j});
        }
    }


    for(int p=0; p<27; p++){
        int z = v[p].size();
        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[p][i]-v[p][k])*(v[p][i]-v[p][j])).imag() == 0){
                        char ch = 65+p;
                        cout << ch;
                        return 0;
                    }
                }
            }
        }
    }
    cout << "ongoing";
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: WRONG ANSWER