You are given an n x ninteger matrix grid.

Generate an integer matrix maxLocalof size (n - 2) x (n - 2)such that:

(资料图)

maxLocal[i][j]is equal to the largest value of the 3 x 3matrix in gridcentered around row i + 1and column j + 1.

In other words, we want to find the largest value in every contiguous 3 x 3matrix in grid.

Return the generated matrix.

Example 1:

Input: grid = [[9,9,8,1],[5,6,2,6],[8,2,6,4],[6,2,2,2]]

Output: [[9,9],[8,6]]

Explanation: The diagram above shows the original matrix and the generated matrix.Notice that each value in the generated matrix corresponds to the largest value of a contiguous 3 x 3 matrix in grid.

Example 2:

Input: grid = [[1,1,1,1,1],[1,1,1,1,1],[1,1,2,1,1],[1,1,1,1,1],[1,1,1,1,1]]

Output: [[2,2,2],[2,2,2],[2,2,2]]

Explanation: Notice that the 2 is contained within every contiguous 3 x 3 matrix in grid.

居然没超时，我不理解。。。。

Runtime: 2 ms, faster than 96.57% of Java online submissions for Largest Local Values in a Matrix.

Memory Usage: 43.9 MB, less than 16.09% of Java online submissions for Largest Local Values in a Matrix.