How To debug This?

My Code has a wrong answer in Test case 7. I have tried to reproduce the wrong Output. But Never Managed to do it. So i tried to get the Data my Algorithm was Working with. In other Blogs I have read, that i should Check for some key differences in the Test case and Then output the data i Need. Even that didn‘t work. Example How can i be shure that isn‘t a bug?. Would be happy if you‘d help me.