Изменения

digraph G { a [label="a" shape=circle]; b [label="b" shape=circle];

d [label="d" shape=circle];

{ rank=same; b c d }

e -> d [label="7" dir=none style=dotted]; b -> a [label="3" dir=none style=bold]; a -> e [label="1" dir=none style=bold]; b -> c [label="5" dir=none style=dotted]; a -> c [label="4" dir=none style=bold]; e -> c [label="6" dir=none style=dotted]; c -> d [label="2" dir=none style=bold]; }