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)

using System;
using System.Collections.Generic;

class Procon
{
  public Procon() {}
  static void Main(string[] args)
  {
    new Procon().Do();
  }

  Scanner cin;

  public void Do()
  {
    cin = new Scanner();
    int N = cin.nextInt();
    int M = cin.nextInt();
    int R = cin.nextInt();

    int[] r = cin.arrayInt();

    int[,] x = new int[N, N];
    int MAX = int.MaxValue / 2 - 1;
    for (int i=0; i<N; i++) 
    {
      for (int j=0; j<N; j++) 
      {
        if (i==j) 
        {
          x[i,j] = 0;
        } else 
        {
          x[i,j] = MAX;
        }
      }
    }

    for (int i=0; i<M; i++) 
    {
      int a = cin.nextInt();
      int b = cin.nextInt();
      int c = cin.nextInt();
      x[a-1, b-1] = c;
      x[b-1, a-1] = c;
    }

    for (int k=0; k<N; k++) 
    {
      for (int i=0; i<N; i++) 
      {
        for (int j=0; j<N; j++)
        {
          x[i, j] = Math.Min(x[i,j], x[i, k] + x[k, j]);
        }
      }
    }

    int[] cr = new int[R];
    for (int i=0; i<R; i++) 
    {
      cr[i] = i;
    }

    long min = long.MaxValue / 2 - 1;;
    do 
    {
      int tmp = 0;
      for (int j=1; j<R; j++) 
      {
        tmp += x[r[cr[j-1]]-1, r[cr[j]]-1];
      }
      min = Math.Min(min, tmp);
    } while(next_permutation(cr));

    Console.WriteLine(min);
  }

  public static bool next_permutation<T>(T[] array) where T : IComparable<T> 
  {
    int end = array.Length - 1;
    int last = end;
    while (true)
    {
      int pos = last - 1;
      if (array[pos].CompareTo(array[last]) < 0)
      {
        int i;
        for (i=end;; i--) {
          if (array[pos].CompareTo(array[i])<0) {
            break;
          }
        }
        T tmp = array[pos];
        array[pos] = array[i];
        array[i] = tmp;
        Array.Reverse(array, last, end - last + 1);
        return true;
      }
      last --;
      if (last == 0 )
      {
        return false;
      }
    }
  }
}

class Scanner
{
  string[] s;
  int i;
  int max_i;

  public Scanner()
  {
    s = new string[0];
    max_i = 0;
    i = 0;
  }

  public string nextString()
  {
    if (i >= s.Length) {
      s = Console.ReadLine().Split(' ');
      max_i = s.Length;
      i = 0;
      if (max_i == 0) {
        return "";
      }
      return s[i++];
    } else {
      return s[i++];
    }
  }

  public int nextInt()
  {
    return int.Parse(nextString());
  }


  public long nextLong()
  {
    return long.Parse(nextString());
  }

  public double nextDouble()
  {
    return double.Parse(nextString());
  }

  public string[] arrayString()
  {
    return Console.ReadLine().Split(' ');
  }

  public int[] arrayInt()
  {
    string[] str = Console.ReadLine().Split(' ');
    int[] array = new int[str.Length];
    for (int i=0; i<str.Length; i++) {
      array[i] = int.Parse(str[i]);
    }
    return array;
  }

  public long[] arrayLong()
  {
    string[] str = Console.ReadLine().Split(' ');
    long[] array = new long[str.Length];
    for (int i=0; i<str.Length; i++) {
      array[i] = long.Parse(str[i]);
    }
    return array;
  }

  public double[] arrayDouble()
  {
    string[] str = Console.ReadLine().Split(' ');
    double[] array = new double[str.Length];
    for (int i=0; i<str.Length; i++) {
      array[i] = double.Parse(str[i]);
    }
    return array;
  }
}