You don’t just want to sort the data, you actually want to collect a list of overlapping pairs, (or more like you want to collect the list of pairs that have ch

You don’t just want to sort the data, you actually want to collect a list of overlapping pairs, (or more like you want to collect the list of pairs that have changed since last time). Using a built in sort will give you the same complexity, but iterating over 10000 elements again to gather this list is an overhead that you can avoid with a DIY approach