How to choose between map and unordered_map? - Stack Overflow
Dec 10, 2012 · Suppose I wanted to map data with a string as the key. What container should I have chosen, map or unordered_map? unordered_map takes up more memory so let's …
Choosing between std::map and std::unordered_map [duplicate]
Aug 19, 2016 · Now that std has a real hash map in unordered_map, why (or when) would I still want to use the good old map over unordered_map on systems where it actually exists? Are …
Is there any advantage of using map over unordered_map in case …
A recent talk about unordered_map in C++ made me realize that I should use unordered_map for most cases where I used map before, because of the efficiency of lookup ( amortized O(1) vs. …
C++ unordered_map using a custom class type as the key
Jun 10, 2013 · You can define a comparison function for an unordered_map separately, instead of using the equality comparison operator (operator==). This might be helpful, for example, if you …
c++ - How std::unordered_map is implemented - Stack Overflow
c++ unordered_map collision handling , resize and rehash This is a previous question opened by me and I have seen that I am having a lot of confusion about how unordered_map is …
Iterating over unordered_map C++ - Stack Overflow
Jun 15, 2018 · std::unordered_map is an implementation of hash table data structure, so it will arrange the elements internally according to the hash value using by std::unordered_map. But …
stl - C++ std::unordered_map complexity - Stack Overflow
The decision to use a regular map vs unordered_map should be based on whether you need a relative strict weak ordering of your keys retained. If you do, you need a regular map. If you …
Why can't I compile an unordered_map with a pair as key?
unordered_map<size_t,double> Map; We can now use Map[key(i,j)]=value or Map.find(key(i,j)) to operate on the map. Every make_pair now becomes calling the inline key function. This …
What is the quickest way of inserting/updating …
My general experience is most people misinterpret which things are drags on their performance. I'd expect the performance difference between the OP's code and either solution here to be …
maps and unordered_maps time complexity analysis - Stack …
Aug 21, 2020 · The data structure behind map is rb-tree while unordered_map uses hash table as its data structure. So we can analayze these two containers via anaylayzing rb-tree and hash …