P1571 眼红的Medusa

#include <bits/stdc++.h>
using namespace std;
long long a = 0, b = 0, c[100005] = {0}, d[100005] = {0}, ab = 0, f[100005];
bool g[100005];

int main()  {
	cin >> a >> b;

	for (long long i = 0; i < a; i++) {

		scanf("%d", &c[i]);
		f[i] = c[i];
	}

	sort(c, c + a);

	for (long long i = 0; i < b; i++) {

		scanf("%d", &d[i]);
	}

	sort(d, d + b);

	for (long long i = 0; i < a; i++) {

		for (; ab < b; ab++) {

			if (c[i] == d[ab]) {
				for (long long j = 0; j < a; j++) {

					if (c[i] == f[j]) {
						g[j] = 1;
					}
				}

				break;
			} else if (c[i] < d[ab]) {
				break;
			}
		}
	}

	for (long long i = 0; i < a; i++) {

		if (g[i]) {
			cout << f[i] << ' ';
		}
	}

	return 0;
}