题解

#include <cstdio>
#include <iostream>

using namespace std;

bool covered(int x, int y, int x1, int y1, int x2, int y2) {
	return x >= x1 && x <= x2 && y >= y1 && y <= y2;
}

int main() {
	int x1, y1, x2, y2;
	cin >> x1 >> y1 >> x2 >> y2;
	int x3, y3, x4, y4;
	cin >> x3 >> y3 >> x4 >> y4;
	int corner_num = 0;
	if (covered(x1, y1, x3, y3, x4, y4)) corner_num++;
	if (covered(x1, y2, x3, y3, x4, y4)) corner_num++;
	if (covered(x2, y1, x3, y3, x4, y4)) corner_num++;
	if (covered(x2, y2, x3, y3, x4, y4)) corner_num++;
	if (corner_num < 2) {
		cout << (x2 - x1) * (y2 - y1);
	} else if (corner_num == 4) {
		cout << 0;
	} else {
		int xl = max(x1, x3);
		int xr = min(x2, x4);
		int yl = max(y1, y3);
		int yr = min(y2, y4);
		cout << (x2 - x1) * (y2 - y1) - (xr - xl) * (yr - yl);
	}
}