question: void scramble ( ) { initialSize = getSize ( ) ; int a [ ] = new int [ initialSize . height / 2 ] ; double f = initialSize . width / ( double ) a . length ; for ( int i = a . length ; -- i >= 0 ; ) { a [ i ] = ( int ) ( i * f ) ; } for ( int i = a . length ; -- i >= 0 ; ) { int j = ( int ) ( i * Math . random ( ) ) ; int t = a [ i ] ; a [ i ] = a [ j ] ; a [ j ] = t ; } arr = a ; }
target:  Fill the array with random numbers from 0..n-1.