Question

Who knows how to use (and explain) the so-called "Big Oh"?

Answer 1

I will assume u don't want me to bore u with that...:-)

Answer 2

.....you scare me......

Answer 3

http://en.wikipedia.org/wiki/Big_O_notation#Example

Answer 4

...right...

Answer 5

you found a scarier answerer than you...

Answer 6

That's a simple example, not scary at all (bit like limits in math)

Answer 7

i hate math....

Answer 8

all i know is that Big Oh is used to measure algorithms...what i don't know is how

Answer 9

U know what linear, quadratic and exponential are already.......

Answer 10

somehow....i manage...

Answer 11

Well, let's do the example together, u tell me what u don't get and we go from there...

Answer 12

honestly....i have no idea about it...unlike most of my questions where i know what i'm doing....i only know introduction to this part...which is it is used to measure algorithms

Answer 13

the efficiency of algorithms....

Answer 14

and by that you mean....?

Answer 15

You can take an algorithm and calculate (count) how many steps it will take for a given input.....

Answer 16

and big oh measures that?

Answer 17

Yes, the basic division is like I said before, linear quadratic and exponential (there are some others, logarithmic etc)

Answer 18

interesting

Answer 19

So, you find that the number of steps for input n is given by 4n^2 -2n +2

Then as n becomes larger, the n^2 term dominates...it is quadratic growth.

Answer 20

Call the function T(n)

T(n) is O(n^2)

Answer 21

how do you use big oh then? is it something like programming?

Answer 22

by that i mean if it's a code

Answer 23

I just did use it, it's a way of describing a function, a notation for that.....

Answer 24

The limiting behaviour of a function.

Answer 25

i meant if it's written *with* the code (say C program)

Answer 26

No, it's not.

U would use Big O (and little o) to talk about the code

Answer 27

This particular area is called algorithmic complexity...

Answer 28

oh. so big oh is written with the algorithm?

Answer 29

No, the algorithm does not depend on big O in any way.

The people who analyze the algorithm for efficiency (perhaps also the programmer, depends on the scale) will use big O to describe the efficiency.

Answer 30

i suppose only way to fully understand is to see it for myself

Answer 31

Read the article, like most Wikipedia articles, it looks a lot worse than it actually is because of the encyclopedic writing style.

Answer 32

that was what i said earlier...

Answer 33

OK, try this instead (to start with)

http://en.wikipedia.org/wiki/Time_complexity#Table_of_common_time_complexities

Answer 34

i'd rather just understand its introduction for now....

Answer 35

I gave u the table because there are some algorithms there u might know

eg binary search, bubble sort