add arc_flow version of cutting stock problem with different capacities
add arc_flow version of cutting stock problem with different capacities

or-tools/or-tools,google/or-tools,google/or-tools,google/or-tools,google/or-tools,or-tools/or-tools,or-tools/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools,google/or-tools,or-tools/or-tools