Collect the Most Rocks with Upward and Rightward Moves

A rectangular grid contains a nonnegative number of rocks in each cell. For this practice version, begin at the bottom-left cell and finish at the top-right cell. You may move only one cell right or one cell up at a time. Return the largest total number of rocks you can collect on a valid path. Collect the rocks in every visited cell, including the starting and ending cells. ### Input - `rocks`: a nonempty two-dimensional integer array. Row `0` is the top row, and column `0` is the leftmost column. ### Output Return the maximum collectible total as an integer. ### Constraints and Edge Cases - For this practice version, the grid has between `1` and `200` rows and between `1` and `200` columns. - Each cell contains between `0` and `1000000` rocks. - There are no blocked cells. - Movement cannot go left or down. A path therefore never revisits a cell. - In a one-cell grid, return that cell's rock count. - In a single row or column, the only valid path visits every cell. ### Example 1 ```text rocks = [[1,2,3], [4,5,6]] output = 18 ``` Move right across the bottom row, then up to the destination: `4 + 5 + 6 + 3 = 18`. ### Example 2 ```text rocks = [[5], [0], [7]] output = 12 ``` The only path moves upward through all three cells and collects `7 + 0 + 5` rocks.