main.cc

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

float evaluate(string frac) {
    int num = -1, denum = -1;
    string buf;
    for(size_t i = 0; i < frac.length(); i++) {
        if(frac[i] == '/') {
            num = atoi(buf.c_str());
            buf = "";
        } else {
            buf += frac[i];
        }
    }
    denum = atoi(buf.c_str());

    return (float)num / denum;
}

bool check(float n) {
    return floor(n) == (int)n && n >= 1;
}

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

    for(int i = 0; i < cases; i++) {
        string frac1, frac2, frac3;
        cin >> frac1 >> frac2 >> frac3;

        float f1 = evaluate(frac1), f2 = evaluate(frac2), f3 = evaluate(frac3);
        float sum = f1 + f2 + f3;
        float coefficent = sum - 1;
        float x = -2 / coefficent;

        // Comprobar que no hay que partir ningún animal
        bool valid = true;
        valid &= check(f1 * x);
        valid &= check(f2 * x);
        valid &= check(f3 * x);
        if(valid) 
            cout << x-1 << endl;
        else
            cout << "no" << endl;
    }
}