1. 创建Point类，重写GetHashCode和Equals函数。
   这样相同XY坐标的Point对象会返回相同的HashCode，就可以使用HashSet集合对点坐标去重。

        class Point{public double X;public double Y;public Point(double x, double y){X = x; Y = y;}public sealed override int GetHashCode(){int result = 17;result = 37 * result + X.GetHashCode();result = 37 * result + Y.GetHashCode();return result;}public sealed override bool Equals(object obj){if(obj is Point pt){return X == pt.X && Y == pt.Y;}return false;}public sealed override string ToString(){return $"X={X},Y={Y}";}}

2. 使用HashSet集合处理所有点坐标。

        public void TestMethod1(){var hashSet = new HashSet<Point>();hashSet.Add(new Point(0,0));hashSet.Add(new Point(0.1,1.1));hashSet.Add(new Point(0.1,1.1));//返回falsehashSet.Add(new Point(0.1,2));hashSet.Add(new Point(0.1,2));//返回falseforeach(Point pt in hashSet){Console.WriteLine(pt.ToString());}}

输出结果：

X = 0,Y = 0
X = 0.1,Y = 1.1
X = 0.1,Y = 2

如果Point类中不重写GetHashCode和Equals函数，那么上面会输出：

X=0,Y=0
X=0.1,Y=1.1
X=0.1,Y=1.1
X=0.1,Y=2
X=0.1,Y=2