Is one double for loop better than two for loops?

1 pointredxblood3 comments

I mean, is: for(..){ for(..){ } }

better than for(..){} for(..){} ?

May it be in terms of running time, memory, etc. This may be a dumb question, if so, i'm sorry.

It's not a dumb question, this idea is covered at the beginning of every data structures class and is described as Big O Notation.

The difference is the growth rate.

for(..){} for(..){} will grow linearly, or O(n).

Iterating over 10 items will be 20 loops, while iterating over 11 items will only be 22 loops.

for(..){ for(..){ } } grows exponentially, or O(n^2)

Here iterating over 10 items will be 100 loops, and increasing n by 1 (to 11) results in 121 loops.

Typically it preferably to user O(n) over O(n^2).

Thanks a lot! Explained really well ^^

Wouldn't you need them for different purposes? A double for loop would go over a 2 dimensional array while a single for loop cannot.