Heap Sort Queue

Heap.java

public class Heap
{
    private Heap() { }

    public static void sort( Comparable[] pq )
    {
        int n = pq.length;

        for ( int k = n / 2; k >= 1; k-- )
            sink( pq, k, n );

        while ( n > 1 )
        {
            exch( pq, 1, n-- );
            sink( pq, 1, n );
        }
    }


    private static void sink( Comparable[] pq, int k, int n )
    {
        while ( 2*k <= n )
        {
            int j = 2*k;

            if ( j < n && less( pq, j, j + 1 ) ) j++;
            
            if ( !less( pq, k, j ) ) break;
            exch( pq, k, j );
            k = j;
        }
    }

    private static boolean less( Comparable[] pq, int i, int j )
    {
        return pq[ i - 1 ].compareTo( pq[ j - 1 ] ) < 0;
    }

    private static void exch( Object[] pq, int i, int j )
    {
        Object swap = pq[ i - 1 ];
        pq[ i - 1 ] = pq[ j - 1 ];
        pq[ j - 1 ] = swap;
    }

    private static void show( Comparable[] a )
    {
        for ( int i = 0; i < a.length; i++ )
        {
            StdOut.println( a[ i ] );
        }
    }

    public static void main( String[] args )
    {
        String[] a = StdIn.readAllStrings();
        Heap.sort( a );
        show( a );
    }
}