NULL root 's suffix edge points to  Imaginary root, since for a string  of length = 0 has an imaginary suffix string.
root2 . length = 0 ; root2 . suffixEdge = 1 ; tree [ 1 ] = root1 ; tree [ 2 ] = root2 ; ptr = 2 ; currNode = 1 ; s = " forgeeksskeegfor " ; for ( int i = 0 ; i < s . size ( ) ; i ++ ) insert ( i ) ;