What algorithm would pair parcels with a high proportion of property x to a parcel with a low proportion of property x so that the weighted average of the two parcels falls within an upper and lower bound? The algorithm needs to pair a set of parcels to maximise the quantity that fall into the given range. The parcels are of differing size.
For example, suppose I have a table of data that has tonnes of each block and percentage iron in each block. I can process two blocks at the same time to create an average iron percentage. I want to change the sequence of each block to maximise the tonnes that fall inside a percentage iron range.