Description：https://leetcode.com/problems/rectangle-area/
public class Solution {
public int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
int area = (C-A)*(D-B) + (G-E)*(H-F);
if (A >= G || B >= H || C <= E || D <= F) {
return area;
}
int top = Math.min(D, H);
int bottom = Math.max(B, F);
int left = Math.max(A, E);
int right = Math.min(C, G);
return area - (top-bottom)*(right-left);
}
}