Creating a vector of indices of a sorted vector [duplicate]

Answer 1

You can do a sort into another list then a comparison with the unsorted list then a 3rd list where you can store the indices i.e nlog(n) + n^2 or just O(n^2)

Note: this is Pseudo code

vector x = {15, 3, 0, 20};
vector y = sort(x);
vector z;
for(int i = 0; y < y.size(); i++){
   for(int j = 0; j < y.size(); j++){
      if(y[i] == x[j]){
         z.push_back(j);
      }
   }
}