using System;

using System.Collections.Generic;

public static class Program

{

    public static void Main()

    {

        //for the given array of points the result should be 2

        var result = new Ray().solution(new Point2D[] {

            new Point2D { x = -1, y = -2 },

            new Point2D { x = 1, y = 2 },

            new Point2D { x = 2, y = 4 }

        });

        Console.WriteLine(result);

    }

}

​

public class Ray

{

    //do not change the method signature

    public int solution(Point2D[] A) {

        // Stores calculated slopes and regions

        double[] slopes = new double[A.Length];

        int[] regions = new int[A.Length];

        // Iterate over the array and find slopes and regions

        // 0,0 point eliminated

        // if a point has 0 value its region set to counterclockwise-first region

        for(int i=0;i<A.Length;i++) {

            if(A[i].x == 0) {

                if(A[i].y>0)

                    slopes[i] = Double.PositiveInfinity;

                if(A[i].y<0)

                    slopes[i] = Double.NegativeInfinity;

                if(A[i].y == 0)

                    slopes[i] = 0;

            }

            else if(A[i].y == 0) {

                if(A[i].x>0)

                    slopes[i] = +0.0;

                if(A[i].y<0)

                    slopes[i] = -0.0;

            }

            else

                slopes[i] = A[i].y/A[i].x;

            if(A[i].x>=0 && A[i].y>0)

                regions[i]=1;

            if(A[i].x<0 && A[i].y>=0)

                regions[i]=2;

            if(A[i].x<=0 && A[i].y<0)

                regions[i]=3;

            if(A[i].x>0 && A[i].y<=0)

                regions[i]=4;

        }

        // This set holds string that is a concatenation of slope and region value

        // Easy way to count unique tuples

        HashSet<String> uniqueSet = new HashSet<String>();

        for(int i=0;i<regions.Length;i++) {

            // point 0,0 not produce a ray

            if(regions[i]==0)

                continue;

            uniqueSet.Add(slopes[i]+"-"+regions[i]);

        }

        return uniqueSet.Count;

    }

​

}

​

​

public class Point2D

{

    public long x;

    public long y;

}

​