Tanvir's blog

If you have asked for an array where you need to add sum from one position to another position and you must do the work in O(N) time.     Then what should you do?   Then you need to  start the position  where you started counting & set the given value on that position. The next work is to add the  (final+1)  position and subtract the value.     Example:    Add 10 on (1 to 2) position   Add 20 on (2 to 3) position   Add 25 on (2 to 5) position     Addition point set (10 on 1st position:20 on 2nd position:25 on 2nd position)   Subtraction point set (10 on 3rd position:20 on 4th position:25 on 6th position)   Array   Array [1]   Array [2]   Array [3]   Array [4]   Array [5]   Extra   After adding 10   10     -10         After adding 20     20     -20       After adding 25 ...