Map to store index of elements
HashMap < Integer , Integer > mp1 = new HashMap < > ( ) ; HashMap < Integer , Integer > mp2 = new HashMap < > ( ) ; for ( int i = 0 ; i < n ; i ++ ) { mp1 . put ( perm1 [ i ] , i ) ; } for ( int j = 0 ; j < n ; j ++ ) { mp2 . put ( perm2 [ j ] , j ) ; } for ( int i = 0 ; i < n ; i ++ ) {