java 快速排序

import java.util.Comparator;
 import java.util.Random;
   
  public class QuickSort {
      public static final Random RND = new Random();
   
      private static void swap(Object[] array, int i, int j) {
          Object tmp = array[i];
          array[i] = array[j];
          array[j] = tmp;
      }
   
      private static <E> int partition(E[] array, int begin, int end, Comparator<? super E> cmp) {
          int index = begin + RND.nextInt(end - begin + 1);
          E pivot = array[index];
          swap(array, index, end);        
          for (int i = index = begin; i < end; ++ i) {
              if (cmp.compare(array[i], pivot) <= 0) {
                  swap(array, index++, i);
              }
          }
          swap(array, index, end);        
          return (index);
      }
   
      private static <E> void qsort(E[] array, int begin, int end, Comparator<? super E> cmp) {
          if (end > begin) {
              int index = partition(array, begin, end, cmp);
              qsort(array, begin, index - 1, cmp);
              qsort(array, index + 1,  end,  cmp);
          }
      }
   
      public static <E> void sort(E[] array, Comparator<? super E> cmp) {
          qsort(array, 0, array.length - 1, cmp);
      }
      
      
      public static void main(String args[])
      {
       Integer array[]=new Integer[]{19, 1, 10, 14, 16, 4, 7, 9, 3, 2, 8, 5, 11};
       
       sort(array,new IntComparator());
       
       for(int i=0;i<array.length;i++){
        System.out.print(array[i]+" "); 
       }
      }      

static class IntComparator implements Comparator<Integer>{//static必須
      public int compare(Integer o1, Integer o2) {
        if(o1< o2){
         return -1;
        }else if(o1 == o2){
         return 0;
        }else{
         return 1;
        }
        
       }
       
      }
      
      
      
  }