Difference of Number of Distinct Values on Diagonals

Description

Given a 2D grid of size m x n, you should find the matrix answer of size m x n.

The cell answer[r][c] is calculated by looking at the diagonal values of the cell grid[r][c]:

- Let leftAbove[r][c] be the number of distinct values on the diagonal to the left and above the cell grid[r][c] not including the cell grid[r][c] itself.

- Let rightBelow[r][c] be the number of distinct values on the diagonal to the right and below the cell grid[r][c], not including the cell grid[r][c] itself.

- Then answer[r][c] = |leftAbove[r][c] - rightBelow[r][c]|.

A matrix diagonal is a diagonal line of cells starting from some cell in either the topmost row or leftmost column and going in the bottom-right direction until the end of the matrix is reached.

- For example, in the below diagram the diagonal is highlighted using the cell with indices (2, 3) colored gray:



- Red-colored cells are left and above the cell.

- Blue-colored cells are right and below the cell.





Return the matrix answer.