operation on 2 dimensional hash map C++ - c++

Question

I am currently working on a coding question:
Given an array of strings, return all groups of strings that are anagrams.
For example, Given:
{asch, scah, bva, vba, soa}
return
{ {asch, scah}, {bva, vba}, {soa}}
To solve this question less than O(n^2) time, we should firstly sort each word, and group the sorted words in one set, if the sorted words are the same.
I wanted to use two-dimensional hashmap.
map<string, map<int,string>> container;
to use this two-dimensional hashmap, the first key is the sorted word, the second key is its index in the original sequence, and the value is the original word.
for(int i=0; i<sequence.size();i++)
{
string original_word = sequence[i];
string sorted_word = original_word;
sort(sorted_word.begin(),sorted_word.end());
container[sorted_word][i] = original_word;
}
After this loop, I believe all the anagrams which must have the same sorted_word, will be grouped into the first level of hashmap.
My question is, how should I write the code in order to get the set which has the same sorted_word?
Can I do
for( iterator itr = container.begin(); itr != container.end(); itr++)
{
auto grouped_words = itr.second(); // what is the data type of grouped_word here?
}
correct me if there is anything wrong. Thanks.

Answer 1

I think there's a mistake here:
vector<string, vector<int,string>> container; // ???
As in your question you speak about hash maps, I suppose that you meant:
unordered_map<string, unordered_map<int,string>> container;
In this case, you can use the result as follows:
for( auto itr = container.begin(); itr != container.end(); itr++)
{
auto &grouped_words = itr->second; // prefer a reference
cout << itr->first<<": ";
for (auto &x : grouped_words) {
cout << "\t" << x.first << ":"<< x.second<<endl;
}
}
Here a live demo.
Edit: grouped_words is (here) a reference to an unordered_map<int, string>