[Boost-users] Re: Efficient removal of std::list items

Cory Nelson wrote:

Yep. If you're going where I think you're going (binary search), I was about halfway through the modifications when I opened the email. Lack of sleep will get to you... :(

On Sun, 19 Dec 2004 20:22:01 -0700, Victor A. Wagner Jr. wrote:

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At Sunday 2004-12-19 17:54, you wrote:

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This seems like the type of thing boost may have an answer to, yet I still havn't found it:

I have two std::lists, about 50,000 items in each. The items are all number ranges so two uints start and end. I need to remove one list from the other - exact matches or subranges only. Currently I'm using remove_if() to remove/shrink/split them but it is taking forever, around 30sec.

Anyone know of a better solution?

are the lists sorted?

That'll only work if the ranges are non-overlapping. Otherwise you'll need to use an interval tree to avoid an O(N) search for each interval you want to remove. -- Dave Abrahams Boost Consulting http://www.boost-consulting.com