Imagine a m x n rectangular island bordered by the Pacific Ocean on its left and top sides, and by the Atlantic Ocean on its right and bottom sides. The island is divided into a grid of square cells, where each cell's height above sea level is indicated by an integer matrix called heights.

Due to heavy rainfall, water can flow between adjacent cells (up, down, left, or right) if the neighboring cell's height is not greater than the current cell's height. Additionally, water can flow from any cell adjacent to the ocean into the ocean itself.

Your task is to determine which cells on this island can drain water into both the Pacific and Atlantic oceans simultaneously. The output should be a 2D list of grid coordinates result ，result[i] = [r_i, c_i]where each coordinate (r_i, c_i) represents a cell that meets the criteria.

Example 1:

Input: heights = [[1,2,1,5,5],[1,3,5,5,1],[1,5,5,3,1],[5,3,3,2,1],[5,2,2,1,1]]
Output: [[0,3],[0,4],[1,2],[1,3],[2,1],[2,2],[3,0],[4,0]]

Explanation: 
The following cells can flow to the Pacific and Atlantic oceans, as shown below:
[0,3]:[0,3] -> Pacific Ocean,[0,3] -> [0,4] -> Atlantic Ocean
[0,4]:[0,4] -> Pacific Ocean,[0,4] -> Pacific Ocean
[1,2]:[1,2] -> [1,3] -> [0,3] -> Pacific Ocean,[1,2] -> [1,3] -> [0,3] -> [0,4] -> Atlantic Ocean
[1,3]:[1,3] -> [0,3] -> Pacific Ocean,[1,3] -> [0,3] -> [0,4] -> Atlantic Ocean
[2,1]:[2,1] -> [2,0] -> Pacific Ocean,[2,1] -> [3,1] -> [4,1] -> Atlantic Ocean
[2,2]:[2,2] -> [2,1] -> [2,0] -> Pacific Ocean,[2,2] -> [2,1] -> [3,1] -> [4,1] -> Atlantic Ocean
[3,0]:[3,0] -> Pacific Ocean,[3,0] -> [4,0] -> Atlantic Ocean
[4,0]:[4,0] -> Pacific Ocean,[4,0] -> Atlantic Ocean

Example 2:

Input: heights = [[2,1],[1,2]]
Output: [[0,0],[0,1],[1,0],[1,1]]
Explanation: The water can flow from all cells to the Pacific and Atlantic oceans.

Example 3:

Input: heights = [[1,2],[2,1]]
Output: [[0,1],[1,0]]

Constraints:

m == heights.length
n == heights[r].length
1 <= m, n <= 200
0 <= heights[r][c] <= 10⁵