设计、实现稀疏矩阵的数据结构 (存储结构和逻辑结构)，并且稀疏矩阵要有以下的函数接口（功能）。

1. 能够修改 (访问) 矩阵中元素的值

2. 矩阵的转置运算得到一个新矩阵

3. 两个矩阵的加法运算得到一个新矩阵

4. 两个矩阵的乘法运算得到一个新矩阵

-Design, implementation sparse matrix data structure (memory and logical structures), and sparse matrix have the following function interface (function). 1. The ability to modify (access) 2. The value of the matrix element of the matrix transpose operation to get a new matrix 3. The two matrix addition operation to get a new matrix 4. Two matrix multiplication to get a new matrix