实现堆

import static java.lang.System.out;//来 自 nowjava - 时代Java



public class Heap {


    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;
          /* from 
          nowjava - 时  代  Java*/

      }

    }

    

    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 boolean less(Comparable[] pq, int i, int j) {

        return pq[i-1].compareTo(pq[j-1]) < 0;

    }

    

    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);

      }

    }

    

    public static void main(String[] args) {