Function ZigZagEncode64

library/cpp/yson/zigzag.h:20–23

    }

    inline ui64 ZigZagEncode64(i64 n) {
        // Note: the right-shift must be arithmetic
        return (ui64(n) << 1) ^ (n >> 63);
    }

    inline i64 ZigZagDecode64(ui64 n) {
        return (n >> 1) ^ -static_cast<i64>(n & 1);