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

A peak element in a 2D grid is an element that is strictly greater than all of its adjacent neighbors to the left, right, top, and bottom.
Given a 0-indexed m x n matrix mat where no two adjacent cells are equal, find any peak element mat[i][j] and return the length 2 array [i,j].
You may assume that the entire matrix is surrounded by an outer perimeter with the value -1 in each cell.
You must write an algorithm that runs in O(m log(n)) or O(n log(m)) time.
 
Please complete the following python code precisely:
```python
class Solution:
    def findPeakGrid(self, mat: List[List[int]]) -> List[int]:
```