Refactor BlockSolver.
Refactor BlockSolver.

yungyuc/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon,yungyuc/solvcon,solvcon/solvcon,yungyuc/solvcon