Data File Format 
"t # N" means the Nth graph,
"v M L" means that the Mth vertex in this graph has label L,
"e P Q L" means that there is an edge connecting the Pth vertex with the Qth vertex. The edge has label L.

NOTICE: 
1.	All labels cannot be 0 or 1,  and it should be larger than 1;
2.  Each data file or query file should end with  t # -1, otherwise it will lead to a bug.
