I thought it was to compute the overlap area of the two rectangles at first...And after I sketch on my paper for some time,I got my code like this:

`int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) { if(B >= H || D <= F || A >= G || C <= E) return 0; else return (min(C,G) - max(E,A)) * (min(D,H) - max(F,B)); }`

And I summit the code,got the "WA".

I checked the last test case and read the question again, found it was to computer the total area.

So I kept the function I wrote above,adding another function to call it,like this:

(The total area equals to the sum of two rectangles minus the overlap area)

`int computeTheTrueArea(int A, int B, int C, int D, int E, int F, int G, int H) { return (C - A) * (D - B) + (G - E) * (H - F) - computeDupArea(A,B,C,D,E,F,G,H); }`