矩形并积

    class Program
    {
        static void Main(string[] args)
        {
            int rectCount =2;
            IList<Rectangle> rects = new List<Rectangle>();
            rects.Add(new Rectangle(0, 0, 2, 2));
            rects.Add(new Rectangle(1, 1, 3, 3));
            //rects.Add(new Rectangle(2, 2, 4, 4));

            UnionRect(rectCount, rects);

            Console.Read();
        }

        static void UnionRect(int ct, IList<Rectangle> rects)
        {
            List<int> x = new List<int>();
            List<int> y = new List<int>();

            foreach (Rectangle r in rects)
            {
                x.Add(r.X1);
                x.Add(r.X2);
                y.Add(r.Y1);
                y.Add(r.Y2);
            }
            x.Sort();
            y.Sort();

            int s = 0;
            for (int i = 1; i <= ct * 2 - 1; i++)
            {
                for (int j = 1; j <= ct * 2 - 1; j++)
                {
                    Rectangle r = new Rectangle(x[i - 1], y[j - 1], x[i], y[j]);
                    foreach (Rectangle re in rects)
                    {
                        if (re.Contain(r))
                        {
                            s += r.Squre();
                            break;
                        }
                    }
                }
            }

            Console.WriteLine("面积：{0}", s);
        }
    }

    public class Rectangle
    {

        public int X1 { get; set; }
        public int X2 { get; set; }
        public int Y1 { get; set; }
        public int Y2 { get; set; }

        public Rectangle(int x1, int y1, int x2, int y2)
        {
            X1 = x1;
            X2 = x2;
            Y1 = y1;
            Y2 = y2;
        }

        //面积
        public int Squre()
        {
            return (X2 - X1) * (Y2 - Y1);
        }

        //是否包含矩形
        public bool Contain(Rectangle smallRect)
        {
            return smallRect.X1 >= this.X1 && smallRect.X2 <= this.X2 && smallRect.Y1 >= this.Y1 && smallRect.Y2 <= this.Y2;
        }
    }

留个记录，求平面内多个矩形的并积，返回面积。

第一次 思路 想以两两运算，发现走不通。

第二次 参考网友思路，分成小块来运算。