223. 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.

关键点是求出两个rectangle重合的部分。

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);
        int x1 = Math.max(A, E);
        int x2 = Math.min(C, G);
        int y1 = Math.max(B, F);
        int y2 = Math.min(D, H);
        int overlap = 0;
        if(x2 > x1 && y2 > y1) {
            overlap = (x2 - x1) * (y2 - y1);
        }
        return area1 + area2 - overlap;
    }
}