1. A system for solving supply chain planning problems, comprising: a database that stores data representing a planning problem of a supply chain network; and a computer coupled with the database and configured to: access the planning problem of the supply chain network stored in the database; model the planning problem as a network of nodes and edges; generate a hierarchical linear programming solution of the planning problem; apply advanced heuristics to the generated hierarchical linear programming solution to obtain an integer feasible solution; formulate a mixed integer program based on the integer solution to generate an optimized global hierarchical solution; and store the generated optimized global hierarchical solution in the database.