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Java Java Data Structures - Retired Exploring the Java Collection Framework Lists

Sina Maleki
Sina Maleki
6,135 Points
Posted by Sina Maleki
Sina Maleki
6,135 Points

Big O Notation problem

Hi everyone who knows any thing about "Drop the less significant terms" subject in Big O Notation? I confused because I don't know why when our runtime is O(n + n^2) we just call O(n^2)?

1 Answer

Jon Kussmann
PLUS
Jon Kussmann
Courses Plus Student 7,254 Points
Jon Kussmann
Jon Kussmann
Courses Plus Student 7,254 Points

Hi Sina,

When we use big O notation, we are concerned with "large" values of n. Let's use your examples of O(n + n^2) and O(n^2). If n is small (let's say 10) then the values are 110 and 100, respectively. There is a 10% difference between them, which you could argue is pretty significant.

Now let's say n is 1,000. The values would then be 1,001,000. This is a 0.1% difference.

As n gets larger, the smaller terms make less of a difference in terms of the overall value, which is why we can drop the smaller terms - they do not make a significant difference to the overall value.

I hope this helps.