Contest dumb fail I've made :(

Fail.java

// what I carelessly wrote
BigInteger value = ciphertext[0];
BigInteger p, o;
if (value.equals(ciphertext[1])) { // << here's careless fail. Never should've done it 
    BigInteger[] factors = factorize(value);
    p = factors[0];
    o = factors[1];
} else {
    p = gcd(value, ciphertext[1]);
    o = value.divide(p);
}
if (p.equals(o)) {
    push.accept(p);
    push.accept(o);
} else {
    for (int i = 1; i < L; ++i) {
        BigInteger x = ciphertext[i];
        if (x.equals(value)) {
            continue;
        }
        boolean test = x.remainder(p).signum() != 0;
        if (i % 2 == 0) {
            test = !test;
        }
        if (test) {
            push.accept(p);
            push.accept(o);
        } else {
            push.accept(o);
            push.accept(p);
        }
        break;
    }
}

// what should I wrote insted to pass (call to `factorize` takes too much time on big numbers)
BigInteger value = ciphertext[0];
int i = 1;
while (value.equals(ciphertext[i])) {
    ++i;
}
BigInteger p = gcd(value, ciphertext[i]);
BigInteger o = value.divide(p);
if (i % 2 == 0) {
    push.accept(p);
    push.accept(o);
} else {
    push.accept(o);
    push.accept(p);
}