if the character of s2 is not present in S1 , then check if previous two ASCII characters are present in S1
else if ( mp . containsKey ( S2 . charAt ( i ) - 1 ) && mp . containsKey ( S2 . charAt ( i ) - 2 ) ) { mp . put ( ( S2 . charAt ( i ) - 1 ) , mp . get ( S2 . charAt ( i ) - 1 ) - 1 ) ; mp . put ( ( S2 . charAt ( i ) - 2 ) , mp . get ( S2 . charAt ( i ) - 2 ) - 1 ) ; } else { return false ; } } return true ; }