What fraction of the values in a matrix must be zero for the sparse matrix representation of Section 12.2 to be more space efficient than the standard two-dimensional matrix representation when data...

What fraction of the values in a matrix must be zero for the sparse matrix representation of Section 12.2 to be more space efficient than the standard two-dimensional matrix representation when data values require eight bytes, array indices require two bytes, and pointers require four bytes?

Write memory manager allocation and deallocation routines for the situation where all requests and releases follow a last-requested, first-released (stack) order.