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