零件供應站設置在哪裡最好？

P---------------Q---------------------------------R <----------流水線

IF A is between PandR (NOT INCLUDE POINT P,Q and R)
the distance of A between P and between R=the distance of PR
then plus the distance between AandQ------------------------PR+AQ
IF A is on Q
then the distance of A between P and between R
plus the distance between AandQ-------------------------------PR
IF A is on P or R
then the distance will be PR+PA/PR+RA

then A on Q