I have a list of list, in different length, and my algorithm runs on every element in the sub lists.

What should be my time complexity?

I don’t know if it’s okay to write O(n * m), as n length of parent list and m is the average length of t

E sub lists, or maybe O(n) as n is the number of total elements.

Please explain what the meaning of the symbols (for example n is the length of the parent list).

### >Solution :

If you have `n`

sublists with `m`

elements each, `n*m`

represents the total number of elements being processed, hence it has a complexity of `O(n*m)`

.

If your sublists have an unequal number of elements, it is okay to summarise it as `O(N)`

, where `N`

is the total number of elements in the array.