A simple way to calculate the coordinates of the bottom-left point and top-right point of the overlapped area.

```
class Solution {
public:
int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
int I, J, K, L;
I = 0; J = 0; K = 0; L = 0;
if ((B <= F) && (F <= D))
J = F;
if ((F <= B) && (B <= H))
J = B;
if ((F <= D) && (D <= H))
L = D;
if ((B <= H) && (H <= D))
L = H;
if ((A <= E) && (E <= C))
I = E;
if ((E <= A) && (A <= G))
I = A;
if ((E <= C) && (C <= G))
K = C;
if ((A <= G) && (G <= C))
K = G;
return ((C - A)*(D - B) - (K - I)*(L - J) + (G - E)*(H - F));
}
};
```