Ex4 Tink Back

using System;
using System.Collections.Generic;

namespace ConsoleApp1
{
    class Program
    {
        public static void Main(string[] args)
        {
            int n, m;
            string? input = Console.ReadLine();
            if (input == null) return;
            n = Convert.ToInt32(input.Split(" ")[0]);
            m = Convert.ToInt32(input.Split(" ")[1]);
            List<List<Tuple<int, int>>> gov = new List<List<Tuple<int, int>>>(n);
            for (int i = 0; i < n; i++)
            {
                gov.Add(new List<Tuple<int, int>>());
            }
            int s;
            for (int i = 0; i < m; i++)
            {
                int e, c;
                input = Console.ReadLine();
                if (input == null) return;
                s = Convert.ToInt32(input.Split(" ")[0]);
                e = Convert.ToInt32(input.Split(" ")[1]);
                c = Convert.ToInt32(input.Split(" ")[2]);
                s--;
                e--;
                gov[s].Add(new Tuple<int, int>(e, c));
                gov[e].Add(new Tuple<int, int>(s, c));
            }
            s = 0;

            List<int> d = new List<int>(n);
            List<bool> u = new List<bool>(n);
            for (int i = 0; i < n; i++)
            {
                d.Add(1000000000);
                u.Add(false);
            }
            d[s] = 0;
            for (int i = 0; i < n; ++i)
            {
                int v = -1;
                for (int j = 0; j < n; ++j)
                    if (!u[j] && (v == -1 || d[j] < d[v]))
                        v = j;
                if (d[v] == 1000000000)
                    break;
                u[v] = true;

                for (int j = 0; j < gov[v].Count; ++j)
                {
                    int toGov = gov[v][j].Item1,
                        length = gov[v][j].Item2;
                    if (d[v] + length < d[toGov])
                    {
                        d[toGov] = d[v] + length;
                    }
                }
            }
            int answer = 0;
            for (int i = 0; i < n; i++)
                answer += d[i];
            Console.WriteLine(answer);
        }
    }
}