You are given a 2D integer matrix grid of size n x m, where each element is either 0, 1, or 2. A V-shaped diagonal segment is defined as:

给你一个大小为 n x n 的整数方阵 grid。返回一个经过如下调整的矩阵：

You are given an n x n square matrix of integers grid. Return the matrix such that:

请你判断一个 9 x 9 的数独是否有效。只需要 根据以下规则 ，验证已经填入的数字是否有效即可。

Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: