产地A_i

销地B_j

产量

1

2

∙∙∙

n

1

c₁₁

c₁₂

c_1n

a₁

2

c₂₁

c₂₂

c_2n

a₂

m

c_m1

c_m2

c_mn

a_m

销量

b₁

b₂

∙∙∙

b_n