'''
900 500 300
700 500 300
0 100 200

Output: 300 (0 -> 100 -> 200 -> 300)

• Top-down view of hiking area
• Each number => height of that cell
• Goal: find the height of the highest accessible cell
• A cell is accessible if:
  • Height = 0; or
  • Adjacent to another accessible cell, height difference <= 100

'''

Note: There can be many zeros .

Looking for solution