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

Given an array of integers, write a method to find indices m and n such that if you sorted elements m through n, the entire array would be sorted. Minimize n - m (that is, find the smallest such sequence).
Return [m,n]. If there are no such m and n (e.g. the array is already sorted), return [-1, -1].
Please complete the following python code precisely:
```python
class Solution:
    def subSort(self, array: List[int]) -> List[int]:
```