Date: 06/15/06 (Algorithms)    Keywords: java

I know that a stable sort is a sorting algorithm that doesn't change the order of elements that are already in order.

What I don't understand is why this is so important. Because it seems like it shouldn't matter if elements that are equal are re-arranged in another equal order.

But I've seen and heard things which make me think there's an importance to stable sorts that I'm not getting. For example, the Java documentation from Sun says: "the algorithm used by sort does not have to be a mergesort, but it does have to be stable." So, clearly, it's regarded as being very important...

Source: http://community.livejournal.com/algorithms/77719.html