Given two sparse integer matrices `A`

and `B`

. Return the result of `AB`

.

This is a companion discussion topic for the original entry at https://algo.monster/problems/sparse_matrix_multiplication/

Given two sparse integer matrices `A`

and `B`

. Return the result of `AB`

.

This is a companion discussion topic for the original entry at https://algo.monster/problems/sparse_matrix_multiplication/

Note that sparse matrice typically use different data structures that store only (or mainly) the nonzero elements.

The time complexity of this solution (without sparse data structures) is O(A_row * B_col * B_row).