$ g++ a29.cpp graph.cpp linear.cpp lt.cpp; a.exe
srand=1143800479
mode=0 ltexcess=41 liexcess=1.60482
mode=1 ltexcess=41 liexcess=1.80464
mode=2 ltexcess=41 liexcess=6.41375
mode=3 ltexcess=41 liexcess=1.50066