tree 428b0d20172148ed82a1dee08c6e08088901670b
parent 8ecb36eec61f119f500a805b82438aadb3396a19
author Li Wenhao <gliwenhao@gmail.com> 1248849908 +0800
committer Li Wenhao <gliwenhao@gmail.com> 1248849908 +0800

the vertex index should be "first + i".