how could I initialize unordered_map< vector<int> >?

Question

I met a question in my work

There is an unordered_map on vector<int> in my c++ class
like this unordered_map < int, vector<int> >

so how could I initialize the nested container so that when I insert a key to the hash table and the value(vector) will be ten zero ?

Answer 1

You can use list initialization:

std::unordered_map<int, std::vector<int>> m
  { { 2, std::vector<int>(10, 0) }
  , { 5, std::vector<int>(10, 0) }
  , { 6, std::vector<int>(10, 0) }
  , { 9, std::vector<int>(10, 0) }
  };