Check Constant Values along Down-Right Diagonals

### Problem Return whether every diagonal running from upper left to lower right in matrix contains one repeated value. Single-cell diagonals satisfy the condition. ```cpp class Solution { public: bool isToeplitzMatrix(vector<vector<int>>& matrix); }; ``` ### Examples **Example 1:** ```text matrix = [[4,7,2],[9,4,7]] Output: true Explanation: Every cell with an upper-left neighbor matches that neighbor. ``` **Example 2:** ```text matrix = [[4,7],[9,5]] Output: false Explanation: The diagonal containing 4 and 5 differs. ``` ### Constraints - Rectangular matrix dimensions are each in [1,20]. - Entries are integers from 0 through 99. ### Contract considerations Only down-right diagonals matter. ```hint Read the boundary condition Which local equality connects consecutive members of a diagonal? ``` ### Boundary reminders Only down-right diagonals matter. ### Optional extensions - How would you check a disk-backed matrix when memory can retain only one row? - How would you process it if even a complete row cannot fit, retaining the necessary diagonal boundary between chunks?