spoj_wrapper_1

bool readToken(FILE* stream, string &s, int maxLen) {
    int c = ' ';
    s = "";
    while(isspace(c)) c = getc(stream);
    if (c == EOF) return false;
    while(!isspace(c) && c != EOF) {
        s.push_back((char)c);
        if ((int)s.length() > maxLen) return false;
        c = getc(stream);
    }
    return true;
}
bool readLong(FILE* stream, int64_t &x) {
    string s;
    if (!readToken(stream, s, 20)) return false;
    ll sgn = 1;
    if (s[0] == '-') {
        sgn *= -1;
        s = s.substr(1, (int)s.length() - 1);
    }
    for (char c : s) if (!isdigit(c)) return false;
    if ((int)s.length() > 19) return false;
    uint64_t y = 0;
    for (char c : s) y = y * 10 + (uint64_t)(c - '0');
    if (y > ((uint64_t)1 << 63)) return false;
    if (y == ((uint64_t)1 << 63)) {
        if (sgn == -1) {
            x = 1;
            x <<= 62;
            x *= -1;
            x += x;
            return true;
        } else {
            return false;
        }
    }
    x = sgn * (int64_t)y;
    return true;
}
bool readLong(FILE* stream, int64_t &x, int64_t L, int64_t R) {
    if (!readLong(stream, x)) return false;
    if (x < L || x > R) return false;
    return true;
}
bool readInt(FILE* stream, int &x, int L, int R) {
    int64_t xx = 0;
    if (!readLong(stream, &xx, L, R)) return false;
    x = xx;
    return true;
}