3148 - Maximum Difference Score in a Grid.

Medium

You are given an m x n matrix grid consisting of positive integers. You can move from a cell in the matrix to any other cell that is either to the bottom or to the right (not necessarily adjacent). The score of a move from a cell with the value c1 to a cell with the value c2 is c2 - c1.

You can start at any cell, and you have to make at least one move.

Return the maximum total score you can achieve.

Example 1:

Input: grid = \[\[9,5,7,3],8,9,6,1,6,7,14,3,2,5,3,1]

Output: 9

Explanation: We start at the cell (0, 1), and we perform the following moves:

• Move from the cell (0, 1) to (2, 1) with a score of 7 - 5 = 2.

• Move from the cell (2, 1) to (2, 2) with a score of 14 - 7 = 7.

The total score is 2 + 7 = 9.

Example 2:

Input: grid = \[\[4,3,2],3,2,1]

Output: \-1

Explanation: We start at the cell (0, 0), and we perform one move: (0, 0) to (0, 1). The score is 3 - 4 = -1.

Constraints:

• m == grid.length

• n == grid[i].length

• 2 <= m, n <= 1000

• <code>4 <= m * n <= 10⁵</code>

• <code>1 <= gridj<= 10⁵</code>