Nrthugu

I have two ArrayList which has the date time which contains entry and exit say

EntryTime ExitTime

1. '2018-10-04 07:00:00' '2018-10-04 11:00:00'


2. '2018-10-04 08:00:00' '2018-10-04 08:30:00'


3. '2018-10-04 09:00:00' '2018-10-04 09:40:00'


4. '2018-10-04 10:00:00' '2018-10-04 10:30:00'

Entry-Exit data is in first ArrayList and data from 2 to 4 is another ArrayList.

Now, the entry-exit which you see at the top 1, I need to bifurcate that time because that is a manual entry made to the system which I am storing in the first array and the rests are system generated which are in the second array. so from 2 till 4, I cannot alter the data which is correct. I need to alter only the first record which is a manual entry. I need to make them distinct and non-overlap and my final result will be like this:

   EntryTime                     ExitTime

1. 
   '2018-10-04 07:00:00' '2018-10-04 07:59:00'


2. '2018-10-04 08:00:00' '2018-10-04 08:30:00'


3. '2018-10-04 09:00:00' '2018-10-04 09:40:00'


4. '2018-10-04 10:00:00' '2018-10-04 10:30:00'


5. 
   '2018-10-04 08:31:00' '2018-10-04 08:59:00'


6. 
   '2018-10-04 09:41:00' '2018-10-04 09:59:00'


7. '2018-10-04 10:31:00' '2018-10-04 11:00:00'

The bolded DateTime(5 to 7 i.e in the result section) is now made distinct and non-overlapped whereas the data in the first section is the same from 2 to 4. The changed values are from 5 to 7.
I am not able to think for should I loop through the ranges and cut the time.
Please help and tell me if you need any other information.
I searched enough but could not find the required answer or it could be I failed to understand.

If the 2-4 entries are sorted chronologically you could just loop through the system generated entries, and for the i-th position, you could check if there is a gap between the i-th (the current entry) exit date and the i+1-th (the next one) entry date, and if there is, then check the other ArrayList to see if there is an entry that begins before and ends after the "gap" you found in the system generated ArrayList.

Pseudocode:

for(int i=0; i<arrayList2.size()-1; i++){



  if(arrayList2[i].exitDate is_before arrayList2[i+1].startDate){



    fillTheGapIfPossible(arrayList2[i], arrayList2[i+1]);



  }



} 



fillTheGapIfPossible(entry1, entry2){



  for(int i=0; i<arrayList1.size(); i++){



    if(arrayList1[i].entry is_before entry1.exitDate &&

       arrayList1[i].exitDate is_before entry2.entryDate){



         makeNewEntry(entry1.endDate, entry2.startDate);



    }



  }



}

Where arrayList2 is the system generated list.