对0 1 2进行 排序

#include <iostream>
#include <cstring>

using namespace std;

const int N = 100010;
int q[N];

void quick_sort(int q[], int l, int r)
{
    int red = 0, white = 0, blue = r;
    while (l <= r) // 一定要加上等于号
    {
        if (q[l] == 0)
        {
            swap(q[l], q[red++]);
            l++;
        }else if (q[l] == 1)
        {
            l++;
        }else if (q[l] == 2)
        {
            swap(q[l], q[blue--]);
            r--;
        }

    }

}
int main()
{
    int m;
    scanf("%d", &m);
    for(int i = 0; i < m; i++) scanf("%d", &q[i]);

    quick_sort(q, 0, m - 1);
    for(int i = 0; i < m; i++) printf("%d ", q[i]);
    return 0;
}