There are many questions in this website asking for finding number of arrangements under different constraints. All of them are similar, but sometimes different approaches are needed for these problems.
I have now answered some of them with the help of a tool and added to community wiki. Some of these questions which I answered using the tool are given below. There are many such questions available
Is it good if I answer more questions using this tool by adding to community wiki because after some days, I may end up in adding many such answers because these questions are appearing very frequently.