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in STL, map is implemented by RB tree, while hashmap is implemented via hash

Another one.
While std::map is in C++ standard, the hash_map is not in standard. So typically it is not recommended to be used. However some STL implementations have it.

map :
comparison at each node to get correct value
hashmap :
uses hash function to correct map key;
constant lookup;
collision may occuer. so can increase linear time

In STL, map is implemented by RB Tree whereas Hashmap is implemented by linkedlists/vectors
Map does have duplicates. HashMap has.
Map does not have collisions.
Map has a complexity O(logn), hashmaps generally have O(1).

map: elements are sorted. most operation complexities O(logn).
hashmap: elements are random. most operation complexities amortized O(1), worst case O(n)

Map is implemented through binary search tree where it key are always sorted internally. Since it has to traverse the tree to insert or delete, it slower than unordered_map (hashmap) which takes constant time to insert and retrieve.