Is String's subscript O(n) when given a lot of combining code points?

[tera]

@Karl

When count says:

O(n), where n is the length of the string.

By "length" it means code-unit length, not the number of characters. Obviously it must visit every code-unit to determine the length of the string, and indeed it scales linearly as your tests show.

The simple fix in this case would be:

O(n + m), where n is the length of the string, m is the total length of all characters in the string.