11 KiB
| title | TARGET DECK | FILE TAGS | tags | ||
|---|---|---|---|---|---|
| Order of Growth | Obsidian::STEM | algorithm::complexity |
|
Overview
The running time of an algorithm is usually considered as a function of its input size. How input size is measured depends on the problem at hand. For instance, algorithms/sorting/index algorithms have an input size corresponding to the number of elements to sort.
%%ANKI Basic How is the running time of a program measured as a function? Back: As a function of its input size. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic How do you determine the input size used to measure an algorithm's running time? Back: This depends entirely on the specific problem/algorithm. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic What concrete measure is typically used to measure running time? Back: The number of primitive operations executed. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic What abstract measure is typically used to measure running time? Back: It's order of growth. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic Why does Cormen et al. state the scope of average-case analysis is limited? Back: What constitutes an "average" input isn't always clear. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic What about running time are algorithm designers mostly interested in? Back: It's order of growth. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic How does order of growth relate to running time? Back: Order of growth measures how quickly running time grows with respect to input size. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic Why are lower-ordered terms ignored when determining order of growth? Back: They become less significant as input size grows. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic Why are leading coefficients ignored when determining order of growth? Back: They become less significant as input size grows. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic Polynomials describing order of growth usually have what two parts ignored? Back: Coefficients and lower-ordered terms. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
How do we simplify \Theta(an^2 + bn + c)?
Back: As \Theta(n^2).
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic Explain why asymptotic notation is useful for both running times and space usage. Back: Asymptotic notation represents functions in a general sense. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI Basic Which running time are algorithm designers typically concerned with? Back: Worst-case running time. Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
In asymptotic notation, how is constant space usage denoted?
Back: Space usage is O(1).
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
How could we replace equality f(n) = \Theta(g(n)) to be less "abusive"?
Back: Replace = with \in.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
How is equality abused in f(n) = \Theta(g(n))?
Back: Here = actually refers to set membership.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
How could we replace 1 in \Theta(1) to be less "abusive"?
Back: Replace 1 with n^0.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
Why does Cormen et al. consider \Theta(1) to be a minor abuse?
Back: This expression does not indicate what variable is tending to infinity.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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\Theta-notation
!
\Theta-notation refers to a strict lower- and upper-bound. It is defined as set \Theta(g(n)) = { f(n) \mid \exists c_1, c_2, n_0 > 0, \forall n \geq n_0, 0 \leq c_1g(x) \leq f(n) \leq c_2g(n) }
%%ANKI
Basic
What kind of mathematical object is \Theta(n)?
Back: A set.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
Using typical identifiers found in \Theta(g(n)), what values do c_1, c_2, and n_0 take on?
Back: Positive constants.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
What names are usually given to the existentially quantified identifers in \Theta(g(n))'s definition?
Back: c_1, c_2, and n_0.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
What name is usually given to the universally quantified identifer in \Theta(g(n))'s definition?
Back: n
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Cloze
Using typical identifiers, f(n) = \Theta(g(n)) satisfies {0} \leq {c_1g(n)} \leq {f(n)} \leq {c_2g(n)}.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using typical identifiers, what is the lower bound of c_1g(n) in \Theta(g(n))?
Back: 0
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using typical identifiers, what is the upper bound of c_1g(n) in the definition of \Theta(g(n))?
Back: f(n)
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using typical identifiers, what is the lower bound of f(n) in the definition of \Theta(g(n))?
Back: c_1g(n)
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using typical identifiers, what is the upper bound of f(n) in the definition of \Theta(g(n))?
Back: c_2g(n)
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using typical identifiers, what is the lower bound of c_2g(n) in \Theta(g(n))?
Back: f(n)
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using typical identifiers, what is the upper bound of c_2g(n) in \Theta(g(n))?
Back: N/A
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Cloze
Given f(n) = \Theta(g(n)), we say {1:g(n)} is an asymptotically {2:tight} bound for {1:f(n)}.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Which notation corresponds to asymptotically tight bounds?
Back: \Theta-notation.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Every member of \Theta(g(n)) is expected to be asymptotically what?
Back: Nonnegative.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
What does it mean for function f(n) to be asymptotically nonnegative?
Back: f(n) \geq 0 whenever n is sufficiently large.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
What does it mean for function f(n) to be asymptotically positive?
Back: f(n) > 0 whenever n is sufficiently large.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
What condition must g(n) satisfy such that otherwise \Theta(g(n)) is empty?
Back: g(n) must be asymptotically nonnegative.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
What does \Theta(-n) evaluate to?
Back: \varnothing
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Why is it \Theta(-n) = \varnothing?
Back: Because -n is not asymptotically nonnegative.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
How is \Theta(g(n)) defined?
Back: \{ \exists c_1, c_2, n_0 > 0, \forall n \geq n_0, 0 \leq c_1g(n) \leq f(n) \leq c_2g(n) \}
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
Using the typical identifiers, what values of n are in the matrix of \Theta(g(n))'s definition?
Back: n \geq n_0
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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%%ANKI
Basic
Which asymptotic notation is this image demonstrating?
!
Back: \Theta-notation
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
END%%
%%ANKI
Basic
What values does the y-axis implicitly range over in the following?
!
Back: Nonnegative values.
Reference: Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).
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References
- Thomas H. Cormen et al., Introduction to Algorithms, 3rd ed (Cambridge, Mass: MIT Press, 2009).