Affine-DO vs. exact solution. Tightness of the Affine-DO solution according to the LP bound compared to the exact approximation. Observe that even for a very small data set, the LP bound is not realistic, and Affine-DO is close to the optimal solution. a. substitutions = 1, a=0, b=1. b. substitutions = 2, a=1, b=1. c. substitutions = 4, a=1, b=3.