3933. Largest Local Values in a Matrix II

Medium17.2% Acceptance

You are given an n x m integer matrix matrix containing non-negative integers.

A non-zero cell (row, col) checks the cells near it as follows:

Let x = matrix[row][col].
Consider every cell within x rows and x columns of (row, col).
Ignore cells that are outside the matrix.
Ignore the cells where both the row distance and column distance are exactly x.

The cell (row, col) is a local maximum if it is non-zero and no considered cell has a value greater than x.

Return an integer denoting the number of local maximums in matrix.

Example 1:

Input: matrix = [[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,2,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0],[0,0,0,0,0,0,0]]

Output: 1

Explanation:

For the non-zero cell (3, 3), x = matrix[3][3] = 2.
The highlighted cells are the considered cells within x rows and x columns of (3, 3).
The four cells with both row and column distances equal to x = 2 are ignored.
No considered cell has a value greater than 2, so (3, 3) is a local maximum.
There are no other non-zero cells, so the answer is 1.

Example 2:

Input: matrix = [[1,2],[3,4]]

Output: 1

Explanation:

Only the cell with value 4 is a local maximum. Every other non-zero cell considers a cell with a greater value.

Example 3:

Input: matrix = [[1,0,1],[0,1,0],[1,0,1]]

Output: 5

Explanation:

For a cell with value 1, the considered cells are the cell itself and its 4-directionally adjacent cells that are inside the matrix.
Each of the five cells with value 1 only considers cells with values 0 or 1, so all five of them are local maximums.

Example 4:

Input: matrix = [[1,1],[1,1]]

Output: 4

Explanation:

All cells have the same value. Therefore, no cell considers another cell with a greater value, so all 4 cells are local maximums.

Constraints: