class Solution {
public:
    bool isToeplitzMatrix(vector<vector<int>>& matrix) {

        unordered_map <int, int> diagonal_value;

        int row = matrix.size();

        if (row == 0) return true;

        int col = matrix[0].size();

        for (int i = 0 ; i < row ; i ++ )
        {
            for (int j = 0 ; j < col ; j ++)
            {
                if (diagonal_value.find(j - i) == diagonal_value.end())
                {
                    diagonal_value[j - i] = matrix[i][j];
                }
                else
                {
                    if (diagonal_value[j - i] != matrix[i][j])
                        return false;
                }
            }
        }
        return true;

    }
};