question: public static long [ ] insertAt ( long [ ] dest , long [ ] src , int offset ) { long [ ] temp = new long [ dest . length + src . length - 1 ] ; System . arraycopy ( dest , 0 , temp , 0 , offset ) ; System . arraycopy ( src , 0 , temp , offset , src . length ) ; System . arraycopy ( dest , offset + 1 , temp , src . length + offset , dest . length - offset - 1 ) ; return temp ; }
target:  Inserts one array into another by replacing specified offset.