80分求助

#include <bits/stdc++.h>
using namespace std;

const int N = 70;

int x, y;
vector<int> a(N), b(N);
set<int > s;

int main() {
	scanf("%d", &x);
	if (x > 0) for (int i = 1; i <= x; i ++) {
		scanf("%d", &a[i]);
		s.insert(a[i]);
	}
	scanf("%d", &y);
	if (y > 0) for (int i = 1; i <= y; i ++) {
		scanf("%d", &b[i]);
		s.insert(b[i]);
	}
	printf("%d\n", x);

	if (x == 0 && y == 0) printf("\n\n");
	else if (x == 0 && y > 0) {
		printf("\n");
		for (int i = 1; i <= y; i ++) printf("%d ", b[i]);
	} else if (x > 0 && y == 0) {
		printf("\n");
		for (int i = 1; i <= x; i ++) printf("%d ", a[i]);
	} else if (x > 0 && y > 0) {
		if (x > y) {
			for (int i = 1; i <= x; i ++) 
				if (find(b.begin(), b.end(), a[i]) != b.end()) printf("%d ", a[i]);
		} else if (x < y) {
			for (int i = 1; i <= y; i ++) 
				if (find(a.begin(), a.end(), b[i]) != a.end()) printf("%d ", b[i]);
		}
		printf("\n");

		for (auto it = s.begin(); it != s.end(); it ++)
			printf("%d ", *it);
	}
	return 0;
}