using System;

using System.Text;

using System.Text.RegularExpressions;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        string multiPolygonsString = "MULTIPOLYGON(((1 1,5 1,5 5,1 8,1 1),(2 2,2 6,3 3,3 2,2 2)),((6 3,9 2,9 4,6 3)))";

        Console.WriteLine(ReverseMultiPolygonString(multiPolygonsString));

    }

    static private string ReverseMultiPolygonString(string multiPolygonsString) 

    {

        string firstLevelRegex = @"(\(\(\((.*?)\)\)\))";

        string secondLevelRegex = @"(\(\((.*?)\)\))";

        string thirdLevelRegex = @"(\((.*?)\))";

        List<List<string>> nestedList = new List<List<string>>();

        Regex regex = new Regex(firstLevelRegex);

        Match matchNestedOne = regex.Match(multiPolygonsString);

        string str = null;

        if (matchNestedOne.Success)

        {

            str = matchNestedOne.Value.Remove(matchNestedOne.Value.LastIndexOf(')'));

            str = str.Remove(0,1);

        }

        regex = new Regex(secondLevelRegex);

        var matches = regex.Matches(str);

        foreach (Match matchNestedTwo in matches)

        {

            str = matchNestedTwo.Value.Remove(matchNestedTwo.Value.LastIndexOf(')'));

            str = str.Remove(0,1);

            regex = new Regex(thirdLevelRegex);

            matches = regex.Matches(str);

            List<string> polygons = new List<string>();

            foreach (Match matchNestedThree in matches)

            {

                str = matchNestedThree.Value.Remove(matchNestedThree.Value.LastIndexOf(')'));

                str = str.Remove(0,1);

                polygons.Add(str);

​

            }

            nestedList.Add(polygons);

        }

        return BuildMultiPolygonString(nestedList);

    }

    static private string BuildMultiPolygonString(List<List<string>> nestedList) 

    {

        StringBuilder sb = new StringBuilder();

        foreach (List<string> polygons in nestedList) {

            sb.Append("(");

            foreach (string polygon in polygons) {

                List<string> toReverse = GetCoordinatesListString(polygon);

                toReverse.Reverse();

                string reversedCoordinates = WriteCoordinatesListString(toReverse);

                sb.Append("(").Append(reversedCoordinates).Append("),");

            }

            sb.Remove(sb.ToString().LastIndexOf(','), 1);

            sb.Append("),");

​

        }

        sb.Remove(sb.ToString().LastIndexOf(','), 1);

        sb.Insert(0,"MULTIPOLYGON(").Append(")");

        return sb.ToString();

    }

    static private string WriteCoordinatesListString(List<string> coordinateList)

    {

​

        StringBuilder sb = new StringBuilder();

        foreach (string coordinatesString in coordinateList) 

        {

            sb.Append(coordinatesString).Append(",");

        }

        string returnedCoordinate = sb.ToString();

        if (returnedCoordinate.LastIndexOf(',') != -1) 

        {

            returnedCoordinate = returnedCoordinate.Remove(returnedCoordinate.LastIndexOf(','));

        }

        return returnedCoordinate;

    }

    static private List<string> GetCoordinatesListString(string coordinateGroup)

    {

        List<string> coordinatesList = new List<string>();

        if (coordinateGroup.IndexOf(',') != -1)

        {

            List<string> inputList = new List<string>(coordinateGroup.Split(','));

            foreach (string coordinatesString in inputList) 

            {

                coordinatesList.Add(coordinatesString.Trim());

            }

        }

        else

        {

            coordinatesList.Add(coordinateGroup);

        }

        return coordinatesList;

    }

}