Search Results
Search type | Search syntax |
---|---|
Tags | [tag] |
Exact | "words here" |
Author |
user:1234 user:me (yours) |
Score |
score:3 (3+) score:0 (none) |
Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
Views | views:250 |
Code | code:"if (foo != bar)" |
Sections |
title:apples body:"apples oranges" |
URL | url:"*.example.com" |
Saves | in:saves |
Status |
closed:yes duplicate:no migrated:no wiki:no |
Types |
is:question is:answer |
Exclude |
-[tag] -apples |
For more details on advanced search visit our help page |
Questions about asymptotic notations such as Big-O, Omega, etc.
8
votes
Why is $3^n = 2^{O(n)}$ true?
$3^n$ grows faster than any exponential function with a base of $2$.
True. This implies that $3^n = O(2^n)$ cannot be true. But what you have here is $2^{O(n)}$.
Recall that $O(f(n))$ is really …
5
votes
Infinite chain of big $O's$
Yes, it's possible to have an infinite chain.
I'm sure you're already familiar with some examples:
$$
O(x) \subseteq O(x^2) \subseteq \ldots \subseteq O(x^{42}) \subseteq \ldots
$$
You have an infin …
2
votes
Accepted
Papadimitrou and standard landau notation
The two definitions are not equivalent. However, the case where they aren't equivalent is one that we aren't interested in for algorithm analysis.
The standard definition implies the Papadimitriou de …
11
votes
Accepted
Big-O and not little-o implies theta?
Let's start with the simple case $g = 1$, and $f$ having positive values only (that's all we care about with functions that represent complexity).
$f \in O(1)$ means that $f$ is bounded: there exist …
11
votes
Justification for neglecting constant factors in Big O
First, as other answers have already explained, $O(3n) = O(n)$, or to put it in words, a function is $O(3n)$ if and only if it is $O(n)$. $f = O(3n)$ means that there exists a point $N$ and a factor $ …
7
votes
Accepted
Can I simplify log(n+1) before showing that it is in O(log n)?
Simplifying the left-hand side is a good strategy. You aren't going to find a simpler expression that's equal to $\log(n+1)$, though. However, since you're only interested in proving that $\log(n+1)$ …
8
votes
Error in the use of asymptotic notation
You've omitted a few steps. It looks like you're attempting to prove by induction that $T(n) = O(n)$, and your proof goes:
Suppose $T(k) = O(k)$ for $k<n$. This means $T(k) \le c \, k$ for some $c …
47
votes
How does one know which notation of time complexity analysis to use?
Big O: upper bound
“Big O” ($O$) is by far the most common one. When you analyse the complexity of an algorithm, most of the time, what matters is to have some upper bound on
how fast the run time¹ g …