using System;

​

/*

"Domino": We are given an S string, representing a domino tile chain. Each tile has an L-R format, where L and R are numbers from the 1..6 range. The tiles are separated by a comma. Some examples of a valid S chain are:

​

1. "6-3"

2. "4-3,5-1,2-2,1-3,4-4"

3. "1-1,3-5,5-2,2-3,2-4"

​

Devise a function that given an S string, returns the number of tiles in the longest matching group within S. A matching group is a set of tiles that match and that are subsequent in S. 

Domino tiles match, if the right side of a tile is the same as the left side of the following tile. "2-4,4-1" are matching tiles, but "5-2,1-6" are not.

​

domino("6-3") // should return 1.

domino("4-3,5-1,2-2,1-3,4-4") // should return 1.

domino("1-1,3-5,5-2,2-3,2-4") // should return 3.

​

Test cases:

​

domino("1-1") // 1

domino("1-2,1-2") // 1

domino("3-2,2-1,1-4,4-4,5-4,4-2,2-1") // 4

domino("5-5,5-5,4-4,5-5,5-5,5-5,5-5,5-5,5-5,5-5") // 7

domino("1-1,3-5,5-5,5-4,4-2,1-3") // 4

domino("1-2,2-2,3-3,3-4,4-5,1-1,1-2") // 3

 */

using System.Collections.Generic;

​

public class Program

{

    class Domino

    {

        public int Left { get; set; }

        public int Right { get; set; }

    }

    public static void Main()

    {

        string S = "1-1,3-5,5-2,2-3,2-4";

        string[] split = S.Split(',');

        int maxChain = 0;

        int v1, v2, cur = 1;

        List<Domino> dominos = new List<Domino>();

        // parse dominos

        for (var i = 0; i < split.Length; i++) {

            string[] vals = split[i].Split('-');

            if (vals.Length == 2) {

                if (int.TryParse(vals[0], out v1) && int.TryParse(vals[1], out v2)) {

                    Domino d = new Domino();

                    d.Left = v1;

                    d.Right = v2;

                    dominos.Add(d);

                }

                else {

                    throw new ArgumentException("Invalid values passed to dominos");

                }

            }

        }

        // get length of chain

        for (var i = 0; i < dominos.Count - 1; i++) {

            if (dominos[i].Right == dominos[i+1].Left) {

                cur++;

            } else {

                if (cur > maxChain) {

                    maxChain = cur;

                    cur = 1;

                }

            }

        }

        if (cur > maxChain) {

            maxChain = cur;

        }

        Console.WriteLine(maxChain);

    }

}