Stores row number of all possible character of the strings
Map < Character , Integer > mp = new HashMap < Character , Integer > ( ) ; mp . put ( ' q ' , 1 ) ; mp . put ( ' w ' , 1 ) ; mp . put ( ' e ' , 1 ) ; mp . put ( ' r ' , 1 ) ; mp . put ( ' t ' , 1 ) ; mp . put ( ' y ' , 1 ) ; mp . put ( ' u ' , 1 ) ; mp . put ( ' i ' , 1 ) ; mp . put ( ' o ' , 1 ) ; mp . put ( ' p ' , 1 ) ; mp . put ( ' a ' , 2 ) ; mp . put ( ' s ' , 2 ) ; mp . put ( ' d ' , 2 ) ; mp . put ( ' f ' , 2 ) ; mp . put ( ' g ' , 2 ) ; mp . put ( ' h ' , 2 ) ; mp . put ( ' j ' , 2 ) ; mp . put ( ' k ' , 2 ) ; mp . put ( ' l ' , 2 ) ; mp . put ( ' z ' , 3 ) ; mp . put ( ' x ' , 3 ) ; mp . put ( ' c ' , 3 ) ; mp . put ( ' v ' , 3 ) ; mp . put ( ' b ' , 3 ) ; mp . put ( ' n ' , 3 ) ; mp . put ( ' m ' , 3 ) ;