returns 0 based indexing of vertex . returns - 1 if no sink exits . returns the vertex number - 1 if sink is found
if ( vertex >= 0 ) System . out . println ( " Sink ▁ found ▁ at ▁ vertex ▁ " + ( vertex + 1 ) ) ; else System . out . println ( " No ▁ Sink " ) ; } }