"Input Copier" by RamiZk is about 6 months ago and he didn't update it . So I decided to write new one with the ability to edit it to suit you!
Any suggestions is very appreciated. If you found a bug please tell me so I can fix it as soon as I can.
How to use it:
Just click on input or output:
It will turn into red when you click it and it will return white after a second.
Tampermonkey or Violentmonkey or any other open source userscript manager is required. The source is available in Greasy Fork: Input Copier
Tampermonkey extension: Tampermonkey
UPD 1.1.0 : Fixed a bug when you can't copy multiple lines (remember to update it to fix the bug).
UPD 1.2.0 : You can copy output too
UPD 1.2.1 : Fixed firefox bug And Added support for the russian site
UPD: Thanks MikeMirzayanov for destroying the script by adding copy button.
UPD: The script is dead now after copy button update on codeforces. but Mike missed one thing that you can not copy the output. Do you want me to create another script that copies the output with the same style? Please let me know in the comments below