On Nov 5, 2013, at 10:17 AM, Chris Paveglio <chris_paveg...@yahoo.com> wrote:
> My exclusions array has many simple objects. Each object has 3 ivars- > (int)itemID1, (int)itemID2, (string)isMutuallyExclusive (not my design but > could be changed if there is a better way). You can build a bitmap out of this for efficient testing. If there are n possible items, then it’s an n x n array of bits where a 1 entry means the two items are mutually exclusive. (To be specific, you index it by computing n * itemID1 + itemID2, then using that as a bit index into the data. Get the byte at index/8, then test the bit at index%8. Or just use an NSMutableIndexSet.) > So, repeat with 100 items in the table, each table row comparing against the > exclusion list which has over 100 entries. It could result in up to 10,000 > comparisons getting tested until the exclusion is found or exhausted. Doing 10,000 lookups in a bitmap won’t take a noticeable amount of time. —Jens _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
