Merge pull request #4 from jvanbrug/master

add fast
Merge pull request #5 from jvanbrug/master

update dynamic routing
Merge pull request #6 from jvanbrug/master

update dynamic routing
Merge pull request #7 from jvanbrug/master

update
Update graph_cases.py
Merge pull request #10 from lanhongjianlr/master

update graph_cases.py