select multiple photos from library but i don't want to select same photo from the album

Question

select multiple photos from library but i don't want to select same photo from the album can any one give me sample code of this,i have searched alote but i didn't get any

- (void)elcImagePickerController:(ELCImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    [self dismissViewControllerAnimated:YES completion:nil];

    NSLog(@"UIImagePickerControllerReferenceURL11 = %@", [info valueForKey:UIImagePickerControllerOriginalImage]);

    for (int k=0; k<[[info valueForKey:UIImagePickerControllerOriginalImage] count]; k++)
    {
        [arr_selectedPhotos addObject:[[info valueForKey:UIImagePickerControllerOriginalImage] objectAtIndex:k]];
    }

    NSLog(@"selectedPhotos = %@", arr_selectedPhotos);
    NSLog(@"selectedPhotos123 = %@", [arr_selectedPhotos objectAtIndex:0]);

    [tbl_SmartPost reloadData];


}