Check if string ' s ▁ length ▁ is ▁ ▁ less ▁ than ▁ pattern ' s length . If yes then no such window can exist
if ( len1 < len2 ) { System . out . println ( " No ▁ such ▁ window ▁ exists " ) ; return " " ; } int hash_pat [ ] = new int [ no_of_chars ] ; int hash_str [ ] = new int [ no_of_chars ] ;