Given a rectangular island represented by a matrix heights where heights[r][c] represents the height above sea level at position (r,c).
The island is surrounded by:
- Pacific Ocean: top and left edges
- Atlantic Ocean: bottom and right edges
Water flow rules:
- Can flow in four directions (up, down, left, right)
- Can only flow to cells of equal or lower height
- Can flow into oceans from adjacent cells
Return all cells where water can flow to both oceans, represented as [row, col] coordinates.
Constraints:
- 1 ≤ matrix dimensions ≤ 100
- 0 ≤ height values ≤ 1000
Examples:
// Example 1:
const heights1 = [
[4, 2, 7, 3, 4],
[7, 4, 6, 4, 7],
[6, 3, 5, 3, 6],
];
console.log(pacificAtlantic(heights1));
// Output: [[0,2],[0,4],[1,0],[1,1],[1,2],[1,3],[1,4],[2,0]]
// Explanation: These cells can flow to both oceans
// Example 2:
const heights2 = [[1], [1]];
console.log(pacificAtlantic(heights2));
// Output: [[0,0],[1,0]]
// Explanation: Both cells can flow to both oceans