Rectangle Area

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.

首先计算出两个长方形的面积，然后计算出它们重叠的面积，最后返回两个面积的差就可以了。代码如下：

public class Solution {
    public int computeArea(int A, int B, int C, int D, int E, int F, int G, int H) {
        int area1 = (C - A) * (D - B);
        int area2 = (G - E) * (H - F);
        return area1 + area2 - (int)getOverlap(A, B, C, D, E, F, G, H);
    }
    public int getOverlap(int A, int B, int C, int D, int E, int F, int G, int H) {
        long w1 = Math.max(A, E);
        long w2 = Math.min(C, G);
        long w = w2 - w1;
        
        long h1 = Math.min(D, H);
        long h2 = Math.max(B, F);
        long h = h1 - h2;
        
        if(w <= 0 || h <= 0) return 0;
        return (int) (w * h);
    }
}