2711 - Difference of Number of Distinct Values on Diagonals.

Medium

Given a 0-indexed 2D grid of size m x n, you should find the matrix answer of size m x n.

The value of each cell (r, c) of the matrix answer is calculated in the following way:

• Let topLeft[r][c] be the number of distinct values in the top-left diagonal of the cell (r, c) in the matrix grid.

• Let bottomRight[r][c] be the number of distinct values in the bottom-right diagonal of the cell (r, c) in the matrix grid.

Then answer[r][c] = |topLeft[r][c] - bottomRight[r][c]|.

Return the matrix answer.

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 reaching the matrix's end.

A cell <code>(r₁, c₁)</code> belongs to the top-left diagonal of the cell (r, c), if both belong to the same diagonal and <code>r₁< r</code>. Similarly is defined bottom-right diagonal.

Example 1:

Input: grid = \[\[1,2,3],3,1,5,3,2,1]

Output: [1,1,0,1,0,1,0,1,1]

Explanation:

The 1^st diagram denotes the initial grid.

The 2^nd diagram denotes a grid for cell (0,0), where blue-colored cells are cells on its bottom-right diagonal.

The 3^rd diagram denotes a grid for cell (1,2), where red-colored cells are cells on its top-left diagonal.

The 4^th diagram denotes a grid for cell (1,1), where blue-colored cells are cells on its bottom-right diagonal and red-colored cells are cells on its top-left diagonal.

• The cell (0,0) contains 1,1 on its bottom-right diagonal and [] on its top-left diagonal. The answer is |1 - 0| = 1.

• The cell (1,2) contains [] on its bottom-right diagonal and 2 on its top-left diagonal. The answer is |0 - 1| = 1.

• The cell (1,1) contains 1 on its bottom-right diagonal and 1 on its top-left diagonal. The answer is |1 - 1| = 0.

The answers of other cells are similarly calculated.

Example 2:

Input: grid = \[\[1]]

Output: [0]

Explanation: - The cell (0,0) contains [] on its bottom-right diagonal and [] on its top-left diagonal. The answer is |0 - 0| = 0.

Constraints:

• m == grid.length

• n == grid[i].length

• 1 <= m, n, grid[i][j] <= 50