Buggy python submission (verdict: Time Limit Exceeded):
import itertools
import sys
input = sys.stdin.readline


def warshall_floyd(D, n):
        for k in range(n):
            for i in range(n):
                for j in range(n):
                    D[i][j] = min(D[i][j], D[i][k]+D[k][j])


def main():
    N, M, R = map(int, input().split())
    r = list(map(int, input().split()))
    D = [[float('inf')]*N for _ in range(N)]
    for i in range(N):
        D[i][i] = 0
    for _ in range(M):
        a, b, c = map(int, input().split())
        D[a-1][b-1] = c
        D[b-1][a-1] = c

    warshall_floyd(D, N)

    ans = float('inf')
    for P in itertools.permutations(r):
        cost = 0
        for i in range(R-1):
            cost += D[P[i]-1][P[i+1]-1]
        ans = min(ans, cost)

    print(ans)


if __name__ == '__main__':
    main()

Fixed submission:
import itertools

def warshall_floyd(D, n):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                D[i][j] = min(D[i][j], D[i][k]+D[k][j])


N, M, R = map(int, input().split())
r = list(map(int, input().split()))
D = [[float('inf')]*N for _ in range(N)]
for i in range(N):
    D[i][i] = 0
for _ in range(M):
    a, b, c = map(int, input().split())
    D[a-1][b-1] = c
    D[b-1][a-1] = c

warshall_floyd(D, N)

ans = float('inf')
for P in itertools.permutations(r):
    cost = 0
    for i in range(R-1):
        cost += D[P[i]-1][P[i+1]-1]
    ans = min(ans, cost)

print(ans)

Buggy python submission (verdict: Runtime Error):
import sys
input = sys.stdin.readline

def main():
        import itertools

    def warshall_floyd(D, n):
        for k in range(n):
            for i in range(n):
                for j in range(n):
                    D[i][j] = min(D[i][j], D[i][k]+D[k][j])


    N, M, R = map(int, input().split())
    r = list(map(int, input().split()))
    D = [[float('inf')]*N for _ in range(N)]
    for i in range(N):
        D[i][i] = 0
    for _ in range(M):
        a, b, c = map(int, input().split())
        D[a-1][b-1] = c
        D[b-1][a-1] = c

    warshall_floyd(D, N)

    ans = float('inf')
    for P in itertools.permutations(r):
        cost = 0
        for i in range(R-1):
            cost += D[P[i]-1][P[i+1]-1]
        ans = min(ans, cost)

    print(ans)


if __name__ == '__main__':
    main()

Fixed submission:
import itertools

def warshall_floyd(D, n):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                D[i][j] = min(D[i][j], D[i][k]+D[k][j])


N, M, R = map(int, input().split())
r = list(map(int, input().split()))
D = [[float('inf')]*N for _ in range(N)]
for i in range(N):
    D[i][i] = 0
for _ in range(M):
    a, b, c = map(int, input().split())
    D[a-1][b-1] = c
    D[b-1][a-1] = c

warshall_floyd(D, N)

ans = float('inf')
for P in itertools.permutations(r):
    cost = 0
    for i in range(R-1):
        cost += D[P[i]-1][P[i+1]-1]
    ans = min(ans, cost)

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import itertools

def warshall_floyd(D, n):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                D[i][j] = min(D[i][j], D[i][k]+D[k][j])


N, M, R = map(int, input().split())
r = list(map(int, input().split()))
D = [[float('inf')]*N for _ in range(N)]
for i in range(N):
    D[i][i] = 0
for _ in range(M):
    a, b, c = map(int, input().split())
    D[a-1][b-1] = c
    D[b-1][a-1] = c

warshall_floyd(D, N)

ans = float('inf')
for P in itertools.permutations(r):
    cost = 0
    for i in range(R-1):
        cost += D[P[i]-1][P[i+1]-1]
    ans = min(ans, cost)

print(ans)

Fixed submission:
import itertools

def warshall_floyd(D, n):
    for k in range(n):
        for i in range(n):
            for j in range(n):
                D[i][j] = min(D[i][j], D[i][k]+D[k][j])


N, M, R = map(int, input().split())
r = list(map(int, input().split()))
D = [[float('inf')]*N for _ in range(N)]
for i in range(N):
    D[i][i] = 0
for _ in range(M):
    a, b, c = map(int, input().split())
    D[a-1][b-1] = c
    D[b-1][a-1] = c

warshall_floyd(D, N)

ans = float('inf')
for P in itertools.permutations(r):
    cost = 0
    for i in range(R-1):
        cost += D[P[i]-1][P[i+1]-1]
    ans = min(ans, cost)

print(ans)