如何在二维数组中找到最常用的元素？除了二维数组之外，不允许使用任何其他数组

def find_most_common_element(matrix):
    count_dict = {}
    max_count = 0
    most_common_element = None

    for row in matrix:
        for element in row:
            if element in count_dict:
                count_dict[element] += 1
            else:
                count_dict[element] = 1

            if count_dict[element] > max_count:
                max_count = count_dict[element]
                most_common_element = element

    return most_common_element

# 示例用法
matrix = [[1, 2, 3], [4, 2, 1], [1, 2, 3]]
most_common_element = find_most_common_element(matrix)
print("最常用的元素是:", most_common_element)