In case I want to read later on what the shifting was about: https://stackoverflow.com/a/16155417/2848941

Took me a moment, but I finally understood it. - You're saying if you move two numbers, you can get something that's bigger than the starting one and still smaller than if you move just one. - Should include one of those in your small number test cases, just so people don't think it's just big ones that do that...

Input is 890, then your thing switched 8 and 9 (to get 980), but he's saying you can do better, (to get 908, which is even closer to original number, i.e. smallest step).

The test cases and errors I got were really useful for making my code better. Felt like a "tip" each time one of the testcases failed in a way that I didn't expect and guided my progress. - Really good practice, thanks for making this!

Just so I understand the process, how did you know "àÇÃČśŮ" were the special characters I was checking? -- How embarrasing, I just saw: I only tested example cases? Guess that is thinking outside the box to just see if I made that beginner mistake :D -- am a beginner afterall, haha.