HDU ACM 11 2034 人见人恨的A-B（此题题目有问题，不要纠结代码为何可以AC）

#include <iostream>
using namespace std;
int main()
{
int m, n, y;
int Lu[200], Yi[200], Zheng[200], Hui[200];
while (cin >> m >> n)
{
if (m == 0 && n == 0)
break;
memset(Zheng, 0, sizeof(Zheng));
y = 0;
for (int i = 0; i < m; i++)
cin >> Lu[i];
for (int i = 0; i < n; i++)
cin >> Yi[i];
for (int i = 0; i < m; i++)
for (int x = 0; x < n; x++)
if (Lu[i] == Yi[x])
Zheng[i] = 1;
for (int i = 0; i < m; i++)
if (Zheng[i] == 0)
Hui[y++] = Lu[i];
for (int i = 0; i < y; i++)
for (int x = i; x < y; x++)
if (Hui[i] > Hui[x])
swap(Hui[i], Hui[x]);
if (y == 0)
cout << "NULL";
else
for (int i = 0; i < y; i++)
cout << Hui[i] << ' ';
cout << endl;
}
return 0;
}