快速排序--Java实现代码

来源：互联网发布：芝加哥艺术学院知乎编辑：程序博客网时间：2024/06/05 17:53
public class Quicksort { private static final int CUTOFF=10; public static void main(String[] args) { Integer[] arr={8,1,4,9,0,3,5,2,7,6,11,17,12,13,14,15,16,18,19,20,21,23,22}; quicksort(arr); for(Integer aa:arr){ System.out.print( aa+","); } } public static <AnyType extends Comparable<? super AnyType>> void quicksort(AnyType[] a){ quicksort(a,0,a.length-1); } private static <AnyType extends Comparable<? super AnyType>> AnyType median3(AnyType[] a,int left,int right){ int center = (left+right)/2; if(a[center].compareTo(a[left])<0) swapReferences(a,left,center); if(a[right].compareTo(a[left])<0) swapReferences(a,left,right); if(a[right].compareTo(a[center])<0) swapReferences(a,center,right); swapReferences(a,center,right-1); return a[right-1]; } private static <AnyType extends Comparable<? super AnyType>> void quicksort(AnyType[] a,int left,int right){ if(left+CUTOFF <=right){ AnyType pivot = median3(a, left, right); int i=left,j=right - 1; for(;;){ while(a[++i].compareTo(pivot) < 0 ){} while(a[--j].compareTo(pivot)> 0 ){} if(i<j) swapReferences(a,i,j); else break; } swapReferences(a,i,right-1); quicksort(a, left, i-1); quicksort(a, i+1, right); } else System.out.println("please use insertionSort"); insertSort(a,left,right);//user insertionSort } private static <AnyType extends Comparable<? super AnyType>> void swapReferences(AnyType[] a,int left,int right){ AnyType tmp = a[left]; a[left] = a[right]; a[right] = tmp; } public static <AnyType extends Comparable<? super AnyType>> void insertSort(AnyType[] a,int left,int right){ int j; for(int p=left+1;pleft && tmp.compareTo(a[j-1]) < 0;j--) a[j] = a[j-1]; a[j] = tmp; } }}
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