# Thread: Totally confused on time complexities.

1. ## Totally confused on time complexities.

I am studying Computer Science.

Currently we are doing time complexities of loops..

I am confused on how to count the repetitions of the loop..

For example

For ( i=1; i<=n; i++)
For (int j=1; j<=2; j x= 2)

i j reps
1 1-2 2
2 1-2^2 3
3 1-2^2 3
. .
. .
. .
n 1-2^n ?

Do you count the inner loop? Do you add up the previous repetitions?

Im just totally confused.

Any break down would be appreciated. Thanks guys

2. ## Re: Totally confused on time complexities.

My browser shows the third part of the inner "for" as "j x= 2". If this is so, then it is an error because x is not declared and because j cannot be applied to x since j is not a function.