Please solve the programming task below using a self-contained code snippet in a markdown code block.

You are given a 0-indexed binary string s of length n on which you can apply two types of operations:

Choose an index i and invert all characters from index 0 to index i (both inclusive), with a cost of i + 1
Choose an index i and invert all characters from index i to index n - 1 (both inclusive), with a cost of n - i

Return the minimum cost to make all characters of the string equal.
Invert a character means if its value is '0' it becomes '1' and vice-versa.
 
Please complete the following python code precisely:
```python
class Solution:
    def minimumCost(self, s: str) -> int:
```