Problem:
Score : 400 points

Problem Statement

There are N towns in the State of Atcoder, connected by M bidirectional roads.

The i-th road connects Town A_i and B_i and has a length of C_i.

Joisino is visiting R towns in the state, r_1,r_2,..,r_R (not necessarily in this order).

She will fly to the first town she visits, and fly back from the last town she visits, but for the rest of the trip she will have to travel by road.

If she visits the towns in the order that minimizes the distance traveled by road, what will that distance be?

Constraints

2≤N≤200

1≤M≤N×(N-1)/2

2≤R≤min(8,N) (min(8,N) is the smaller of 8 and N.)

r_i≠r_j (i≠j)

1≤A_i,B_i≤N, A_i≠B_i

(A_i,B_i)≠(A_j,B_j),(A_i,B_i)≠(B_j,A_j) (i≠j)

1≤C_i≤100000

Every town can be reached from every town by road.

All input values are integers.

Input

Input is given from Standard Input in the following format:

N M R
r_1 ... r_R
A_1 B_1 C_1
:
A_M B_M C_M

Output

Print the distance traveled by road if Joisino visits the towns in the order that minimizes it.

Sample Input 1

3 3 3
1 2 3
1 2 1
2 3 1
3 1 4

Sample Output 1

2

For example, if she visits the towns in the order of 1, 2, 3, the distance traveled will be 2, which is the minimum possible.

Sample Input 2

3 3 2
1 3
2 3 2
1 3 6
1 2 2

Sample Output 2

4

The shortest distance between Towns 1 and 3 is 4. Thus, whether she visits Town 1 or 3 first, the distance traveled will be 4.

Sample Input 3

4 6 3
2 3 4
1 2 4
2 3 3
4 3 1
1 4 1
4 2 2
3 1 6

Sample Output 3

3

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

// ReSharper disable ArrangeTypeMemberModifiers
// ReSharper disable ConvertIfStatementToSwitchStatement
// ReSharper disable FunctionRecursiveOnAllPaths
// ReSharper disable InconsistentNaming
// ReSharper disable InlineOutVariableDeclaration
// ReSharper disable InvertIf
// ReSharper disable JoinDeclarationAndInitializer
// ReSharper disable MemberCanBeMadeStatic.Global
// ReSharper disable MemberCanBeMadeStatic.Local
// ReSharper disable NonReadonlyMemberInGetHashCode
// ReSharper disable PossibleNullReferenceException
// ReSharper disable RedundantUsingDirective
// ReSharper disable SuggestVarOrType_BuiltInTypes
// ReSharper disable SuggestVarOrType_Elsewhere
// ReSharper disable TailRecursiveCall
// ReSharper disable UnusedMember.Global
// ReSharper disable UnusedMember.Local
// ReSharper disable UseObjectOrCollectionInitializert

#if true && UTAKA_LOCAL

//#if false
#define UTAKA_DEBUG
#endif

//#define TOPCODER

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using static UtakaApp.Util;

namespace UtakaApp
{
    public partial class Program
    {
        /*
        https://atcoder.jp/contests/abc073/tasks/abc073_d
        */

        public const string SiteName    = "AtCoder";
        public const string ContestName = "abc073";
        public const string ProblemName = "D";

        public void Solve()
        {
            int N    = cin.ReadInt;
            int M    = cin.ReadInt;
            int rNum = cin.ReadInt;

            int[] R = cin.ReadIntArray(rNum);

            for (int i = 0; i < rNum; i++)
            {
                R[i]--;
            }
            
            Array.Sort(R);

            const long Inf = 1L << 60;

            long[][] dp = new long[N][];
            for (int i = 0; i < N; i++)
            {
                dp[i] = new long[N];

                for (int j = 0; j < N; j++)
                {
                    dp[i][j] = i == j ? 0 : Inf;
                }
            }

            for (int i = 0; i < M; i++)
            {
                int  a = cin.ReadInt - 1;
                int  b = cin.ReadInt - 1;
                long t = cin.ReadLong;

                dp[a][b] = t;
                dp[b][a] = t;
            }

            new WarshallFloyd().Calc(dp, Inf);

            long ans = long.MaxValue;

            do
            {
                long totalCost = 0;

                for (int i = 0; i < R.Length - 1; i++)
                {
                    int f = R[i];
                    int t = R[i + 1];

                    totalCost += dp[f][t];
                }

                ans = Math.Min(ans, totalCost);
            } while (NextPermutation(R, 0, R.Length));

            cou.WriteLine(ans);

//            long ans = Inf;
//
//            for (int i = 0; i < N; i++)
//            {
//                long v = 0;
//
//                for (int j = 0; j < N; j++)
//                {
//                    v = Math.Max(v, dp[i][j]);
//                }
//
//                ans = Math.Min(ans, v);
//            }
//
//            cou.WriteLine(ans);
        }

        /// <summary>
        /// シーケンスの次の順列を求めます
        /// </summary>
        /// <typeparam name="T">順列を構成する要素の型</typeparam>
        /// <param name="array">次の順列を求めたいシーケンス</param>
        /// <param name="start">次の順列を求めたい範囲の最初のインデックス</param>
        /// <param name="length">次の順列を求めたい範囲の長さ</param>
        /// <returns>引数arrayが最後の順列ならばfalse、そうでないならtrueを返します</returns>
        public static bool NextPermutation<T>(T[] array, int start, int length)
            where T : IComparable
        {
            int end = start + length - 1;

            // 範囲が狭すぎる
            if (end <= start) return false;

            int last = end;
            while (true)
            {
                int pos = last--;

                if (array[last].CompareTo(array[pos]) < 0)
                {
                    int i;
                    for (i = end + 1; array[last].CompareTo(array[--i]) >= 0;)
                    {
                    }

                    T tmp = array[last];
                    array[last] = array[i];
                    array[i]    = tmp;
                    Array.Reverse(array, pos, end - pos + 1);
                    return true;
                }

                if (last == start) // 最後の順列
                {
                    Array.Reverse(array, start, end - start);
                    return false;
                }
            }

            // ここに来ることはない
            throw new Exception("NextPermutation: Fatal error");
        }
    }


    public class WarshallFloyd
    {
        /// <summary>
        /// WarshallFloyd法で全点対間最短経路を求める
        /// dpはあらかじめ設定済みのものを渡す
        /// </summary>
        public void Calc(long[][] dp, long inf)
        {
            long N = dp.Length;

            // i -> k -> j 
            for (int k = 0; k < N; k++)
            {
                for (int i = 0; i < N; i++)
                {
                    // 負のコストがある場合に対応するため、infを取り除く必要がある
                    if (dp[i][k] == inf) continue;

                    for (int j = 0; j < N; j++)
                    {
                        // 負のコストがある場合に対応するため、infを取り除く必要がある
                        if (dp[k][j] == inf) continue;

                        dp[i][j] = Math.Min(dp[i][j], dp[i][k] + dp[k][j]);
                    }
                }
            }
        }

        /// <summary>
        /// WarshallFloyd法で全点対間最短経路を求め、負の閉路が存在するかを返す
        /// dpはあらかじめ設定済みのものを渡す
        /// </summary>
        public bool CalcAndFindNegativeCycle(long[][] dp, long inf)
        {
            Calc(dp, inf);

            long N = dp.Length;

            for (int i = 0; i < N; i++)
            {
                if (dp[i][i] < 0)
                {
                    return true;
                }
            }

            return false;
        }
    }

//=========================================================================================
// Debug IO
//=========================================================================================

    public partial class Program
    {
        //=========================================================================================
        // Main
        //=========================================================================================

        private readonly ConsoleInput cin;
        private readonly IConsole     cou;

        public Program(ConsoleInput cin, IConsole cou)
        {
            this.cin = cin;
            this.cou = cou;
        }

#if !TOPCODER
        public static void Main(string[] args)
        {
#if UTAKA_LOCAL
//#if false
            new TestCaseCheckerForAtCoder().TestProblems();
#else
            var cin = new ConsoleInput(System.Console.In);
            var console = new MyConsole();
            new Program(cin, console).Solve();
            console.Flush();
#endif
        }
#endif

        public void WriteEnumerable<T>(IEnumerable<T> A, string delimiter = " ")
        {
            var sb = new StringBuilder();
            foreach (T v in A)
            {
                sb.Append(v);
                sb.Append(delimiter);
            }

            if (sb.Length > 0)
            {
                sb.Length--;
            }

            cou.WriteLine(sb.ToString());
        }
    }

    public static class Util
    {
        //=========================================================================================
        // Library
        //=========================================================================================

        public static T[] Array1D<T>(int a, T defaultValue)
            where T : struct
        {
            var ret = new T[a];
            for (int i = 0; i < a; i++)
            {
                ret[i] = defaultValue;
            }

            return ret;
        }

        public static T[] Array1D<T>(int a)
            where T : struct
        {
            var ret = new T[a];
            return ret;
        }

        /// <summary>
        /// 要素数 (a, b) の、defaultValue で満たされた配列を作成します。
        /// </summary>
        /// <typeparam name="T">配列の型</typeparam>
        /// <param name="a">1次元の要素数</param>
        /// <param name="b">2次元の要素数</param>
        /// <param name="defaultValue">デフォルト値</param>
        /// <returns>指定した条件で初期化された配列</returns>
        public static T[,] Array2D<T>(int a, int b, T defaultValue)
            where T : struct
        {
            var ret = new T[a, b];
            for (int i = 0; i < a; i++)
            {
                for (int j = 0; j < b; j++)
                {
                    ret[i, j] = defaultValue;
                }
            }

            return ret;
        }

        public static T[,,] Array3D<T>(int a, int b, int c, T defaultValue)
            where T : struct
        {
            T[,,] ret = new T[a, b, c];

            for (int i = 0; i < a; i++)
            {
                for (int j = 0; j < b; j++)
                {
                    for (int k = 0; k < c; k++)
                    {
                        ret[i, j, k] = defaultValue;
                    }
                }
            }

            return ret;
        }

        /// <summary>
        /// 要素数 (a, b) の、defaultValue で満たされたJag配列を作成します。
        /// </summary>
        /// <typeparam name="T">配列の型</typeparam>
        /// <param name="a">1次元の要素数</param>
        /// <param name="b">2次元の要素数</param>
        /// <param name="defaultValue">デフォルト値</param>
        /// <returns>指定した条件で初期化された配列</returns>
        public static T[][] JagArray2D<T>(int a, int b, T defaultValue)
            where T : struct
        {
            var ret = new T[a][];
            for (int i = 0; i < a; i++)
            {
                var row = new T[b];
                ret[i] = row;

                for (int j = 0; j < b; j++)
                {
                    row[j] = defaultValue;
                }
            }

            return ret;
        }

        /// <summary>
        /// 要素数 (a, b) のdefault値で満たされたJag配列を作成します。
        /// </summary>
        /// <typeparam name="T">配列の型</typeparam>
        /// <param name="a">1次元の要素数</param>
        /// <param name="b">2次元の要素数</param>
        /// <returns>初期化された配列</returns>
        public static T[][] JagArray2D<T>(int a, int b)
            where T : struct
        {
            var ret = new T[a][];
            for (int i = 0; i < a; i++)
            {
                ret[i] = new T[b];
            }

            return ret;
        }

        public static T[][][] JagArray3D<T>(int a, int b, int c, T defaultValue)
            where T : struct
        {
            var ret = new T[a][][];
            for (int i = 0; i < a; i++)
            {
                T[][] aRow = new T[b][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[] bRow = new T[c];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        bRow[k] = defaultValue;
                    }
                }
            }

            return ret;
        }

        public static T[][][] JagArray3D<T>(int a, int b, int c)
            where T : struct
        {
            var ret = new T[a][][];
            for (int i = 0; i < a; i++)
            {
                T[][] aRow = new T[b][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[] bRow = new T[c];
                    aRow[j] = bRow;
                }
            }

            return ret;
        }

        public static T[][][][] JagArray4D<T>(int a, int b, int c, int d, T defaultValue)
            where T : struct
        {
            var ret = new T[a][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][] aRow = new T[b][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][] bRow = new T[c][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[] cRow = new T[d];
                        bRow[k] = cRow;

                        for (int l = 0; l < d; l++)
                        {
                            cRow[l] = defaultValue;
                        }
                    }
                }
            }

            return ret;
        }

        public static T[][][][] JagArray4D<T>(int a, int b, int c, int d)
            where T : struct
        {
            var ret = new T[a][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][] aRow = new T[b][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][] bRow = new T[c][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[] cRow = new T[d];
                        bRow[k] = cRow;
                    }
                }
            }

            return ret;
        }

        public static T[][][][][] JagArray5D<T>(int a, int b, int c, int d, int e, T defaultValue)
            where T : struct
        {
            var ret = new T[a][][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][][] aRow = new T[b][][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][][] bRow = new T[c][][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[][] cRow = new T[d][];
                        bRow[k] = cRow;

                        for (int l = 0; l < d; l++)
                        {
                            T[] dRow = new T[e];
                            cRow[l] = dRow;

                            for (int m = 0; m < e; m++)
                            {
                                dRow[m] = defaultValue;
                            }
                        }
                    }
                }
            }

            return ret;
        }

        public static T[][][][][] JagArray5D<T>(int a, int b, int c, int d, int e)
            where T : struct
        {
            var ret = new T[a][][][][];
            for (int i = 0; i < a; i++)
            {
                T[][][][] aRow = new T[b][][][];
                ret[i] = aRow;

                for (int j = 0; j < b; j++)
                {
                    T[][][] bRow = new T[c][][];
                    aRow[j] = bRow;

                    for (int k = 0; k < c; k++)
                    {
                        T[][] cRow = new T[d][];
                        bRow[k] = cRow;

                        for (int l = 0; l < d; l++)
                        {
                            T[] dRow = new T[e];
                            cRow[l] = dRow;
                        }
                    }
                }
            }

            return ret;
        }

        /// <summary>
        /// ジャグ配列をコピーして返す。
        /// </summary>
        public static T[][] CopyJagArray2D<T>(T[][] source)
            where T : struct
        {
            int   len  = source.Length;
            T[][] dest = new T[len][];

            for (int i = 0; i < len; i++)
            {
                T[] inner       = source[i];
                int innerLength = inner.Length;
                T[] newer       = new T[innerLength];
                Array.Copy(inner, newer, innerLength);
                dest[i] = newer;
            }

            return dest;
        }
    }

    public class IntLargeComparer : IComparer<int>
    {
        public static IntLargeComparer Instance = new IntLargeComparer();

        public int Compare(int x, int y)
        {
            return y - x;
        }
    }

    public class LongLargeComparer : IComparer<long>
    {
        public static LongLargeComparer Instance = new LongLargeComparer();

        public int Compare(long x, long y)
        {
            if (x > y) return -1;
            if (x < y) return 1;
            return 0;
        }
    }

    public static class UtakaExtentions
    {
        /// <summary>
        /// 配列をコピーします
        /// </summary>
        public static T[] Copy<T>(this IList<T> a)
        {
            T[] ret = new T[a.Count];

            for (int i = 0; i < a.Count; i++) ret[i] = a[i];

            return ret;
        }
    }

    public class ConsoleInput
    {
        private readonly char          _separator = ' ';
        private readonly TextReader    _stream;
        private readonly Queue<string> inputStream;

        public ConsoleInput(TextReader stream, char separator = ' ')
        {
            _separator  = separator;
            _stream     = stream;
            inputStream = new Queue<string>();
        }

        public string Read
        {
            get
            {
                if (inputStream.Count != 0)
                {
                    return inputStream.Dequeue();
                }

                var tmp = _stream.ReadLine().Split(_separator);
                for (var i = 0; i < tmp.Length; ++i)
                {
                    inputStream.Enqueue(tmp[i]);
                }

                return inputStream.Dequeue();
            }
        }

        public string ReadLine   => _stream.ReadLine();
        public int    ReadInt    => int.Parse(Read);
        public long   ReadLong   => long.Parse(Read);
        public double ReadDouble => double.Parse(Read);

        public string[] ReadStrArray(long N)
        {
            var ret = new string[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = Read;
            }

            return ret;
        }

        public int[] ReadIntArray(long N)
        {
            var ret = new int[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = ReadInt;
            }

            return ret;
        }

        public int[] ReadIntArrayMinus1(long N)
        {
            var ret = new int[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = ReadInt - 1;
            }

            return ret;
        }

        public long[] ReadLongArray(long N)
        {
            var ret = new long[N];
            for (long i = 0; i < N; ++i)
            {
                ret[i] = ReadLong;
            }

            return ret;
        }
    }

    public interface IConsole
    {
        void Flush();
        void Write(object obj);
        void Write(string str);
        void WriteLine(object obj);
        void WriteLine(string str);
        void WriteLine();
    }

    public class MyConsole : IConsole
    {
        public MyConsole()
        {
            var sw = new StreamWriter(Console.OpenStandardOutput()) {AutoFlush = false};
            Console.SetOut(sw);
        }

        public void Flush()
        {
            Console.Out.Flush();
        }

        public void Write(object obj)
        {
            Write(obj.ToString());
        }

        public void Write(string str)
        {
            Console.Write(str);
        }

        public void WriteLine(object obj)
        {
            WriteLine(obj.ToString());
        }

        public void WriteLine(string str)
        {
            Console.WriteLine(str);
        }

        public void WriteLine()
        {
            Console.WriteLine();
        }
    }

#if UTAKA_LOCAL

    public class DebugConsole : IConsole
    {
        private readonly StringBuilder mSb;

        public DebugConsole()
        {
            mSb = new StringBuilder();
        }

        public void Flush()
        {
            // 何もしない
        }

        public void Write(object obj)
        {
            Write(obj.ToString());
        }

        public void Write(string str)
        {
            mSb.Append(str);
        }

        public void WriteLine(object obj)
        {
            WriteLine(obj.ToString());
        }

        public void WriteLine(string str)
        {
            mSb.AppendLine(str);
        }

        public void WriteLine()
        {
            mSb.AppendLine();
        }

        public string GetAllOutput()
        {
            return mSb.ToString();
        }
    }

#endif

#if UTAKA_LOCAL

    public class TestCaseCheckerForAtCoder
    {
        private string GetDirectoryPath()
        {
            var problemPart = string.IsNullOrEmpty(Program.ProblemName)
                ? ""
                : $"/{Program.ProblemName}";

            return
                $"{Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)}/AlgorithmPrac/{Program.SiteName}/{Program.ContestName}{problemPart}";
        }

        private string GetInputFilePath(int testCaseNumber)
        {
            return $"{GetDirectoryPath()}/sample-{testCaseNumber}.in";
        }

        private string GetOutputFilePath(int testCaseNumber)
        {
            return $"{GetDirectoryPath()}/sample-{testCaseNumber}.out";
        }

        public bool TestProblem(int testCaseNumber)
        {
            var inputFilePath  = GetInputFilePath(testCaseNumber);
            var outputFilePath = GetOutputFilePath(testCaseNumber);

            TextReader inputStream = new StreamReader(inputFilePath);
            var        cin         = new ConsoleInput(inputStream);

            var debugConsoleWriter = new DebugConsole();

            new Program(cin, debugConsoleWriter).Solve();

            var output = debugConsoleWriter.GetAllOutput();

            TextReader outputStream = new StreamReader(outputFilePath);
            var        outputAnswer = outputStream.ReadToEnd();

            Dbg.WriteLine(output);
            Dbg.WriteLine(outputAnswer);

            var isCorrect = output == outputAnswer;

            return isCorrect;
        }

        public void TestProblems(int targetTestCaseNumber = -1)
        {
            if (targetTestCaseNumber >= 0)
            {
                Console.WriteLine($"!!!!!!!!!!!! Check TestCase {targetTestCaseNumber} !!!!!!!!!!");
            }

            bool isSuccessAll = true;

            int testCaseNumber = 0;
            while (true)
            {
                testCaseNumber++;

                bool foundTargetTest = targetTestCaseNumber == testCaseNumber;

                if (targetTestCaseNumber >= 0 && !foundTargetTest)
                {
                    continue;
                }

                var inputFileName = GetInputFilePath(testCaseNumber);
                if (!File.Exists(inputFileName))
                {
                    break;
                }

                Console.WriteLine($"TestCase {testCaseNumber} =====================================================");

                var result = TestProblem(testCaseNumber);

                if (result)
                {
                    Console.WriteLine("Success");
                }
                else
                {
                    isSuccessAll = false;
                    Console.WriteLine("Failure *****");
                }

                if (foundTargetTest)
                {
                    break;
                }
            }

            if (isSuccessAll)
            {
                Console.WriteLine("!!!!!!!!! All Success !!!!!!!!!");
            }
        }
    }

#endif

    public static class Dbg
    {
        [Conditional("UTAKA_DEBUG")]
        public static void WriteLine(string str)
        {
            Console.WriteLine(str);
        }

        [Conditional("UTAKA_DEBUG")]
        public static void WriteLine()
        {
            Console.WriteLine();
        }

        [Conditional("UTAKA_DEBUG")]
        public static void Write(string str)
        {
            Console.Write(str);
        }
    }
}