稀疏矩阵的压缩与还原。

一个矩阵含有非零元素比较少，而零元素相对较多，这样的矩阵称为稀疏矩阵，对稀疏矩阵的存储我们不用完全用二维数组来存储，可以用一个三元组，即任意一个稀疏矩阵可以用一个只有三列的二维数组来存放，要求把给定的稀疏矩阵用为三元组表示；同时把三元组转换为稀疏矩阵形式。

-Sparse matrix compression and reduction.A matrix with nonzero element is less, and zero element is relatively more, so the matrix called sparse matrix, the sparse matrix storage we don t have to entirely in a two-dimensional array to store, you can use a triad, or any one of only three columns of sparse matrix can use a two-dimensional array to store,Asked to put the given sparse matrix by for ternary group said　At the same time convert triples to sparse matrix form.