STL std::unordered_set (std::algorithm generate_n for creation of sets)

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STL std::unordered_set (std::algorithm generate_n for creation of sets) | Modern Cpp Series Ep. 122

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Күн бұрын

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►Lesson Description: In this lesson I give you an introduction to the std::unordered_set data structure which is an unsorted data structure storing unique elements. The advantage is in this case the ability to have average time constant lookup, insertion, and removal. I'll spend some time introducing the concept of a hash table at the start of the lesson, and then I'll also show you how to generate sets using the stl algorithm generate_n.
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Пікірлер: 10

@tanveerasif5978 2 ай бұрын

Thank you so much for wonderful underneath concept.

@MikeShah 2 ай бұрын

Cheers, you are most welcome!

@MightyMoveSemantics 11 ай бұрын

@7:39 Bucket Count (e.g., std::unordered_set s(5);) This is about organizing the internal storage with a specified number of buckets. Elements are distributed among these buckets based on their hash values. Suppose you insert an integer 14. The hash function calculates a hash value, let's say h(14) = 14 for simplicity. The bucket index is then 14 % 5 = 4, so 14 is placed into bucket 4. reserve(5);: This is about optimizing performance by minimizing the number of rehashes when inserting elements. It does so by ensuring there's enough space allocated to hold the specified number of elements without needing to rehash. Am I right?

@MikeShah 11 ай бұрын

That sounds about right to me!

@thestarinthesky_ Жыл бұрын

Thanks Mike for this great video 🤩! I have a question why @23:36 we got that error? I didn't get it quite why.

@MikeShah Жыл бұрын

I think I just had the wrong type -- needed an iterator that can insert.

@shrek1412 Жыл бұрын

may I know difference between unordered_set and unordered_map?

@MikeShah Жыл бұрын

Unordered set only contains keys, whereas unordered map is a key/value pair. (I.e. stores the keys, same as map, but those keys are used to index and return a value)