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Tagged with hash-tables asymptotics
7 questions
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Counting letter frequency in array in O(1) with hash function
I want to calculate the frequency of each character in an array. (e.g ['a', 'b', 'o', 'p']
There are several ways to do this:
A Simple brute-force over the array would need $O(n^2)$ time and $O(n)$ ...
- 167
1
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0
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60
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Cuckoo hashing with a stash: how tight are the bounds on the failure probability?
I was reading this very good summary of Cuckoo hashing.
It includes a result (page 5) that:
A stash of constant sizes reduces the probability of any failure to
fall from $\Theta(1/n)$ to $\Theta(...
- 111
1
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3
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274
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Is the capacity of a hash table a constant value?
In this paper, page 4, it is said:
"...there is always a constant expected number of elements that map to the same slot"
Assume we have a set $S$ of $n$ values, and we want to insert them into a ...
- 111
4
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2
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How exactly Hashing performs better than a Binary Search?
The time complexity of a Binary Search is O(log n) and Hashing is O(1) - so I've read. I have also read that Hashing outperforms Binary search when input is large, for example in millions. But I see ...
- 193
0
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1
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Complexity of inserting an integer to an empty hashtable
What's the complexity of inserting an integer $n$ to an empty hash table? My guess is that it's $O(\log n)$ as we require to scan every bit of $n$ to compute its hash. However, I often see it as $O(1)...
- 171
7
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2
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2k
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Confusion with analysis of hashing with chaining
I was attending a class on analysis of hash tables implemented using chaining, and the professor said that:
In a hash table in which collisions are resolved by
chaining, an search (successful or ...
- 275
0
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3
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What is the average search complexity of perfect hashing?
The lookup time in perfect hash-tables is $O(1)$ in the worst case. Does that simply mean that the average should be $\leq O(1)$?
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