快速排序

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#define N 1000010
using namespace std;
int b[N];
int part(int s, int t){
    int i = 0, j = 0;
    int p = 0;
    i = s;
    j = t;
    p = b[s];
    while(i < j){
        while(i < j && b[j] >= p){
            j--;
        }
        b[i] = b[j];
        while(i < j && b[i] <= p){
            i++;
        }
        b[j] = b[i];
    }
    b[j] = p;
    return j;
}
int quicksort(int s, int t){
    int i = 0;
    if(s < t){
        i = part(s, t);
        quicksort(s, i-1);
        quicksort(i+1, t);
    }
    return 0;
}
int main()
{
    int n = 0, m = 0;
    while (2 == scanf("%d%d", &n, &m)){
        for (int i = 0; i < n; i++) {
            scanf("%d", &b[i]);
        }
        quicksort(0, n-1);
        for (int i = n-1; i > n-1-m; i--) {
            if (i != n-1) {
                printf(" ");
            }
            printf("%d", b[i]);
        }
        printf("\n");
    }
    return 0;
}