[android help] Removing common elements between two different Arraylist

Sorry If you are thinking that it is a repeated post. But the situation is different here. I have read several posts for it but not getting the exact thing I am looking for. I know How to develop a complex logic for this but please take a look this is for android and we can't expect too much processing on the device due to to limited resources available. I have an ArrayList of an bean class objects consisting five fields as Java Bean -- MyShares fileName filePath fileSize isShared Creator I have another ArrayList of String which contains only filepaths. Now what I want is to remove all the common elements between the two arraylist means the file paths in seconds arraylist and file path in first arraylist objects are similar then I have to remove from both of the arraylist But I Don't want a new arraylist which contains the uncommon elemenst But I want to get my both arraylist only without their common elements. Please help me. asked 18 mins ago

You can use an outer loop to scan over the Bean objects, and an inner loop to scan over the file paths. pseudo code: for(Bean i in beans){ for(String p in paths){ if(i.path.equals(p)){ beansToRemove.add(i); pathsToRemove.add(p); } } } beans.removeAll(beansToRemove); paths.removeAll(pathsToRemove); I'm not sure if my extra arraylists to track the removed arraylists go against your question or not since the original arrays remain. If you presort both arrays on the path and keep track of the position in each area (not exhaustive search) you can improve it from n2 to nlgn answered 5 mins ago

	Rough Java code: HashSet commonKeys = new HashSet(); for (Share share : shares) { commonKeys.add(share.filePath); } commonKeys.retainAll(filePaths); for (Iterator it = shares.iterator(); it.hasNext(); ) { Share share = it.next(); if (commonKeys.contains(share.filePath)) { it.remove(); } } filePaths.removeAll(commonKeys); answered 1 min ago

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