1121. Damn Single (25)

#include <iostream>
#include <algorithm>
#include <vector>
#include <string.h>

using namespace std;

int couple[100000], party[100000], num[100000];

int main()
{
	int n;
	scanf("%d", &n);

	memset(couple, -1, sizeof(couple));

	int i, a, b;
	for(i = 1; i <= n; i++)
	{
		scanf("%d%d", &a, &b);

		couple[a] = b;
		couple[b] = a;
	}

	int m;
	scanf("%d", &m);

	int index;
	for(i = 1; i <= m; i++)
	{
		scanf("%d", &index);

		party[index] = 1;
		num[i] = index;
	}

	vector<int> res;
	for(i = 1; i <= m; i++)
	{
		index = num[i];
		if(couple[index] != -1 && party[couple[index]] == 1)
		{
			continue;
		}

		res.push_back(index);
	}

	sort(res.begin(), res.end());

	int size = res.size();
	printf("%d\n", size);

	for(i = 0; i < size; i++)
	{
		if(i > 0)
		{
			printf(" ");
		}

		printf("%05d", res[i]);
	}

	if(size > 0)
	{
		printf("\n");
	}

	system("pause");
	return 0;
}