text: Keep track of the number of shifts required to place elements at same indices
code: else { if ( ! diff . containsKey ( i - Aindex . get ( B [ i ] ) ) ) { diff . put ( i - Aindex . get ( B [ i ] ) , 1 ) ; } else { diff . put ( i - Aindex . get ( B [ i ] ) , diff . get ( i - Aindex . get ( B [ i ] ) ) + 1 ) ; } } }