The document discusses two standard template library containers for storing key-value pairs: unordered_map and map. Unordered_map uses a hash table to provide fast lookup of elements in average O(1) time, but the elements are in random order. Map uses a binary search tree to provide O(logN) lookup time and stores elements in sorted order. Both support insertion, erasure, and lookup of elements using similar functions but have different underlying implementations and time complexities.

1. Level up your coding skills with
the C++ Standard Template
Library (STL):
Maps
BY JOYJIT CHOUDHURY

2. Unordered Map
 unordered_map is an associative container that contains key-value pairs with
unique keys. It allows fast retrieval of individual elements based on their keys.
 Internally, the elements in the unordered_map are not sorted in any particular
order with respect to either their key or mapped values
 Search, insertion, and removal have an average time complexity of O(1)
 It is typically implemented as a hash table
 Defined in the header <unordered_map>
 Belongs to the namespace std
(remember : using namespace std)

3. Insert elements

4. Erase elements

5. Lookup an element

6. Access and Modify an element

7. Map
 map is a sorted associative container that contains key-value pairs
with unique keys. Keys are sorted by using the comparison function
compare
 Search, insertion, and removal have an average time complexity of
O(logN)
 It is typically implemented as a balanced binary search tree
 Defined in the header <map>
 Belongs to the namespace std
(remember : using namespace std)

8. Map
 Search, insertion, and removal of elements with respect to map can
be done in the same way as that for unordered_map using the
functions insert(), erase(), find() and operator[]
 The difference being, the different time complexities of these
operations with respect to the different containers
O(1) : unordered_map vs. O(logN) : map
 The elements in map are stored in a particular order and allow range
based iterations, whereas unordered_map stores the elements in a
random order

13.  That’s not all. There are many other functions
and techniques that could come in handy.
Read about them on cplusplus.com or
cppreference.com or somewhere else. Just
google it !