if I have an array of 10^6 elements. how to store the count of each element. Is there a more efficient way than the map
it is a array of integers
constraints of elements ?
Either use un-ordered map or the best idea:-
Use a special map created by this guy on codeforces, it is the fastest map ever!
if it is 10^9
where is that link not showing
What is the range of the integers? Are they non-negative and \le 10^7?
If this is the case, you can use a frequency table, implemented using an array.
In general cases, you can use an unordered_map which has average complexity of O(1) for insertion/deletion.