#codingexercise
Generate a 2D distance matrix for the nearest distance from each cell as city location to  a parking spot that appears as one or more occupied cells.

 static int[][] getParkingDistanceGrid(int cityLength, int cityWidth, int[] parkingXCoordinates, int[] parkingYCoordinates) {

        var d = new int[cityWidth][];

        for (int i = 0; i < cityWidth; i++)

            d[i] = new int[cityLength];

        for (int i = 0; i < cityWidth; i++)

        {

            for (int j = 0; j < cityLength; j++)

                {

                    var parkingdistances = new List<int>();

                    for (int count = 0; count < parkingXCoordinates.Length; count++)

                    {

                        int distance = GetDistance(i+1, j+1, parkingXCoordinates[count], parkingYCoordinates[count]);

                        parkingdistances.Add(distance);

                    }

                    int min = INT_MAX;

                    for (int k = 0; k < parkingXCoordinates.Length; k++)

                        if (parkingdistances[k] < min)

                           min  = parkingdistances[k];

                    d[i][j] = min; 

                }

        }

        return d;

    }

    static int GetDistance(int r1, int c1, int r2, int c2)

    {

        int deltax = r1 - r2;

        deltax = deltax > 0 ? deltax : 0-deltax;

        int deltay = c1 - c2;

        deltay = deltay > 0 ? deltay : 0-deltay;

        return deltax + deltay;        

    }

Generate a recommendation list of courses taken by the social circle of a user. The recommendation must include courses taken by the members of her social circle but not by her. It must be ranked by the number of attendees to the course. A social circle consists only of the persons direct friends and their direct friends.

public List<string> getRankedCourses(string user) {
    var coursePopularity = new Dictionary<string, int>();
    var circle = new List<string>();
    
    var direct = getDirectFriendsForUser(user);
    circle.AddRange(direct);
    foreach (var friend in direct){
        if (friend != user){
        var directForFriend = getDirectFriendsForUser(friend);
        directForFriend.Remove(user);
        circle.AddRange(directForFriend);
        }
    }
    
    foreach (var person in circle)
    {
        var attended = getAttendedCoursesForUser(person);
        foreach(var course in attended)
        {
            if (!coursePopularity.ContainsKey(course))
            {
                coursePopularity.Add(course,1);   
            }
            else
            {
                coursePopularity[course] += 1;   
            }
        }
    }
    
    foreach(var attending in getAttendedCoursesForUser(user))
    {
     coursePopularity.Remove(attending);   
    }
    List<KeyValuePair<string, int>> ranked = coursePopularity.ToList();
    ranked.Sort(
    delegate(KeyValuePair<string, int> pair1,
    KeyValuePair<string, int> pair2)
    {
        return pair1.Value.CompareTo(pair2.Value);
    }
    );
    
    var recommendations = new List<string>();
    foreach (var kvp in ranked)
        recommendations.Add(kvp.Key);
    recommendations.Reverse();
    return recommendations;

}