Path With Minimum Effort

DESCRIPTION (inspired by Leetcode.com)

A hiking app needs to find the easiest route across terrain. Given a 2D grid where each cell represents the elevation at that point, find the path from the top-left corner to the bottom-right corner that minimizes the "effort".

The effort of moving between two adjacent cells is the absolute difference in their elevations. The effort of a path is the maximum single-step effort along that path.

You can move up, down, left, or right from any cell. Return the minimum effort required.

Example 1:

Input:

heights = [[1,10,2], [2,3,3], [3,2,1]]

Output:

1

Explanation: The cliff (10) has a huge elevation difference. Going around via 1→2→3→2→1 avoids it entirely, with each step having effort at most 1.

Example 2:

Input:

heights = [[4,3,2], [2,6,3], [3,2,1]]

Output:

2

Explanation: The center peak (6) would require effort 3 to cross. Going around the top: 4→3→2→3→1 keeps maximum effort at 2.