patternMinor
standard sequential algorithm with polylog runtime?
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polylogwithruntimestandardsequentialalgorithm
Problem
At the Wikipedia article on time complexity, only a PRAM example is given for polylogarithmic time.
Let $T(n)$ denote the largest number of steps used by a machine to reach a final state on any input with size $n$ bits.
Is there a program for a standard sequential model of computation (e.g. a Turing machine or a sequential random-access machine), solving some natural problem, so that $T(n) \in \Theta((\log n)^k)$ for some fixed $k>1$?
Let $T(n)$ denote the largest number of steps used by a machine to reach a final state on any input with size $n$ bits.
Is there a program for a standard sequential model of computation (e.g. a Turing machine or a sequential random-access machine), solving some natural problem, so that $T(n) \in \Theta((\log n)^k)$ for some fixed $k>1$?
Solution
Where each operation is $ O\left(\log^kn\right)$ amortized/expected; I don't know if necessarily $\Theta\left(\log^kn\right)$:
for Connectivity, Minimum Spanning Tree, 2-Edge,
and Biconnectivity (PDF)
Polylogarithmic Time per Operation (PDF)
-
Maintaining Dynamic Sequences under Equality Tests
in Polylogarithmic Time (PDF)
-
Distances and point-sets:
There are also many algorithms with polylogarithmic factors; $\tilde {O}(\cdot)$ is notation that is used when hiding polylogarithmic factors. So $O\left(n\log^k n \right)\in\tilde {O}(n)$.
- Dynamic graph connectivity algorithms
- Poly-Logarithmic Deterministic Fully-Dynamic Algorithms
for Connectivity, Minimum Spanning Tree, 2-Edge,
and Biconnectivity (PDF)
- Dynamic graph connectivity in polylogarithmic worst case time (PDF, slides)
- Fully Dynamic 2-Edge Connectivity Algorithm in
Polylogarithmic Time per Operation (PDF)
- Lists of connectivity problems
-
Maintaining Dynamic Sequences under Equality Tests
in Polylogarithmic Time (PDF)
-
Distances and point-sets:
- Maintaining the miminal distance of a point set in polylogarithmic time (PDF, $O\left(\log^2n\right)$, Smid)
- New techniques for some dynamic closest-point and farthest-point problems ($O\left(\log^D n\right)$ Supowit)
- New Techniques For Exact And Approximate Dynamic Closest-Point Problems (PDF, Kapoor, Smid, $O\left(\log^D n \log \log n\right)$, though cites others with just $O(polylog)$)
- TOPP 63: Dynamic Planar Nearest Neighbors, lists 3 papers with data structures that have operations that run in $O\left(log^k n\right)$ time
- Point location algorithms,
- Monotone subdivisions, without fractional cascading, query-time is $O\left(\log^2 n\right)$
- Best known algorithms for point-location in higher-dimensions ($\gt 2$) have a trade-off; $O\left(\log n\right)$ query-time has large memory requirements that make them unscaleable. Reducing the memory requirements (for example to $O\left(n\log n\right)$ results in query-times of $O\left(\log^k n\right)$
- Efficient Partition Trees (PDF, Matousek, $O\left(\log^2 n\right)$ insertion time)
- An Implicit Data Structure For The Dictionary Problem That Runs In Polylog Time (Munro, $O\left(\log^2n\right)$)
There are also many algorithms with polylogarithmic factors; $\tilde {O}(\cdot)$ is notation that is used when hiding polylogarithmic factors. So $O\left(n\log^k n \right)\in\tilde {O}(n)$.
Context
StackExchange Computer Science Q#16622, answer score: 6
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