When you run the installer, Windows may show a blue box saying “Windows protected your PC”. This is not a virus warning. It appears because the app does not carry a paid code-signing certificate, and Windows shows it for every program it has not seen many times before.
To continue: click More info, then Run anyway.
If your browser also warns while downloading, choose Keep. The file is served from codejudge.xyz over HTTPS — check the address bar if you want to be sure.