Questions tagged [algorithm]
An algorithm is a sequence of well-defined steps that defines an abstract solution to a problem. Use this tag when your issue is related to algorithm design.
algorithm
13,438
questions
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How do I check if an array includes a value in JavaScript?
What is the most concise and efficient way to find out if a JavaScript array contains a value?
This is the only way I know to do it:
function contains(a, obj) {
for (var i = 0; i < a.length; i++...
- 75.1k
5379
votes
43
answers
836k
views
What is a plain English explanation of "Big O" notation?
I'd prefer as little formal definition as possible and simple mathematics.
- 61.8k
1677
votes
22
answers
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What is the best algorithm for overriding GetHashCode?
In .NET, the GetHashCode method is used in a lot of places throughout the .NET base class libraries. Implementing it properly is especially important to find items quickly in a collection or when ...
- 49.3k
980
votes
24
answers
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Big O, how do you calculate/approximate it?
Most people with a degree in CS will certainly know what Big O stands for.
It helps us to measure how well an algorithm scales.
But I'm curious, how do you calculate or approximate the complexity of ...
- 18.3k
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votes
57
answers
2.2m
views
Removing duplicates in lists
How can I check if a list has any duplicates and return a new list without duplicates?
- 20.6k
1042
votes
10
answers
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How can I find the time complexity of an algorithm?
I have gone through Google and Stack Overflow search, but nowhere I was able to find a clear and straightforward explanation for how to calculate time complexity.
What do I know already?
Say for code ...
- 47.6k
859
votes
41
answers
1.1m
views
How do I generate all permutations of a list?
How do I generate all the permutations of a list? For example:
permutations([])
[]
permutations([1])
[1]
permutations([1, 2])
[1, 2]
[2, 1]
permutations([1, 2, 3])
[1, 2, 3]
[1, 3, 2]
[2, 1, 3]
[2, ...
- 13.6k
1016
votes
66
answers
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Count the number of set bits in a 32-bit integer
8 bits representing the number 7 look like this:
00000111
Three bits are set.
What are the algorithms to determine the number of set bits in a 32-bit integer?
1167
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50
answers
1.2m
views
Calculate distance between two latitude-longitude points? (Haversine formula)
How do I calculate the distance between two points specified by latitude and longitude?
For clarification, I'd like the distance in kilometers; the points use the WGS84 system and I'd like to ...
- 15.3k
665
votes
32
answers
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How do you compare float and double while accounting for precision loss?
What would be the most efficient way to compare two double or two float values?
Simply doing this is not correct:
bool CompareDoubles1 (double A, double B)
{
return A == B;
}
But something like:
...
- 6,691
648
votes
77
answers
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Algorithm to return all combinations of k elements from n
I want to write a function that takes an array of letters as an argument and a number of those letters to select.
Say you provide an array of 8 letters and want to select 3 letters from that. Then ...
579
votes
15
answers
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What is the most efficient/elegant way to parse a flat table into a tree?
Assume you have a flat table that stores an ordered tree hierarchy:
Id Name ParentId Order
1 'Node 1' 0 10
2 'Node 1.1' 1 10
3 'Node 2' 0 ...
- 336k
221
votes
30
answers
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views
Rolling or sliding window iterator?
I need a rolling window (aka sliding window) iterable over a sequence/iterator/generator. (Default Python iteration could be considered a special case, where the window length is 1.) I'm currently ...
- 5,820
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votes
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Cartesian product of multiple arrays in JavaScript
How would you implement the Cartesian product of multiple arrays in JavaScript?
As an example,
cartesian([1, 2], [10, 20], [100, 200, 300])
should return
[
[1, 10, 100],
[1, 10, 200],
[1, ...
- 20.4k
2060
votes
30
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What is tail recursion?
Whilst starting to learn lisp, I've come across the term tail-recursive. What does it mean exactly?