QuickSort 快速排序 基于伪代码实现

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伪代码

 quicksort(A, lo, hi)
   if lo < hi
     p = partition(A, lo, hi)
     quicksort(A, lo, p - 1)
     quicksort(A, p + 1, hi)

 partition(A, lo, hi)
     pivot = A[hi]
     i = lo //place for swapping
     for j = lo to hi - 1
         if A[j] <= pivot
             swap A[i] with A[j]
             i = i + 1
     swap A[i] with A[hi]
     return i

Java实现

     public void quickSort(int[] a,int lo, int hi){
         if(lo<hi){
             int p=partition(a, lo, hi);
             quickSort(a,lo,p-1);
             quickSort(a, p+1, hi);
         }
     }
     public int partition(int[] a,int lo, int hi){
         int i,j,privot;
         privot=a[hi];
         i=lo;
         for(j=lo;j<=hi-1;j++){
             if(a[j]<privot){
                 swap(a, i, j);
                 i++;
             }
         }
         swap(a,i,hi);
         return i;
     }
     public void swap(int[] a,int lo,int hi){
         int s=a[lo];
         a[lo]=a[hi];
         a[hi]=s;
     }