Which Map Maintains Insertion Order. If you're doing hundreds of thousands of lookups, the difference between O (log n) lookup for std::map. We can achieve the given task using LinkedHashMap. Here's a link to Boost's documentation for unordered_map. You can use the vector to keep track of the insertion order and the hash table to do the frequent lookups. Keys with null or empty strings are not allowed. Which Map Maintains Insertion Order
Which Map Maintains Insertion Order Where as TreeMap places the elements according to the supplied Comparator. Here's a link to Boost's documentation for unordered_map. That said, this is an oddly specific situation where the implementation of Map actually matters.
Set is an unordered collection, it doesn't maintain any order.
To iterate through map contents in insert order, we need to create a slice that keeps track of each key.
Which Map Maintains Insertion Order Is order maintained in HashMap Java? We can achieve the given task using LinkedHashMap. So, LinkedHashMap is the right implementation of Map that you need to use when you want to keep the elements in the same order that they were inserted.