Thuật toán Quick Sort

void quicksort(int a[10000] , int n , int low, int high) {

    /**< sap xep theo chieu tang dan  */

    int i = low ;

    int j = high ;

    int x = a[(low+high) /2] ;

    do {

        while (a[i] < x) i++ ;

        while (a[j]> x ) j -- ;

        if(i<=j) {

            int temp = a[i] ;

            a[i] = a[j] ;

            a[j] = temp ;

            i++ ;

            j-- ;

        }

    }

    while (i<= j) ;

    if( low<j) quicksort(a,n,low,j) ;

    if(i<high ) quicksort(a,n,i,high) ;

}