题目：
Find the total area covered by two rectilinear rectangles in a 2D plane.
Each rectangle is defined by its bottom left corner and top right corner as shown in the figure.
Assume that the total area is never beyond the maximum possible value of int.
题目解答：本题是要求出两个矩阵在二维空间中所占的面积。做法是，求出两个矩阵的面积，再减去他们的交集。
代码如下：
class Solution {
public:
int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
if( (A > C) || (B > D) || (E > G) || (F > H) )
{
return 0;
}
int a = (C - A) * (D - B);
int b = (G - E) * (H - F);
int intersection = 0;
int A_ = max(A,E);
int B_ = max(B,F);
int C_ = min(C,G);
int D_ = min(D,H);
if((A_ < C_) && (B_ < D_))
{
intersection = (C_ - A_) * (D_ - B_);
}
return a + b - intersection;
}
};