Maximum Coins in Grid

Maximum Coins in Grid

Given a 2D matrix where each cell represents the number of coins in that cell, determine the maximum number of coins you can collect starting from the top-left corner (matrix[0][0]) and moving only to the right or down, reaching the bottom-right corner of the matrix.

Write a function that takes a 2D matrix as input and returns the maximum number of coins collected.

Example 1:

Input: [[0, 3, 1, 1], [2, 0, 0, 4], [1, 5, 3, 1]]
Output: 12
Explanation: The path 0 → 2 → 1 → 5 → 3 → 1 collects the maximum coins (0 + 2 + 1 + 5 + 3 + 1 = 12).

Example 2:

Input: [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Output: 29
Explanation: The path 1 → 2 → 3 → 6 → 9 collects the maximum coins (1 + 2 + 3 + 6 + 9 = 21).

Constraints:

• The matrix dimensions are m x n.
• Each cell contains a non-negative integer.