Hackerrank prob

from collections import defaultdict

class Graph:
    
    def __init__(self):
        self.neighbours=defaultdict(list)
    
    def addEdge(self,u,v):
        self.neighbours[u].append(v)
        self.neighbours[v].append(u)
        
    
    def bfs(self,i, n):

        level = [-1] * (n+1)
        queue = []
        level[i] = 0
        queue.append(i)

        while queue:
            head=queue.pop(0)
            for k in self.neighbours[head]:
                if level[k] == -1:
                    level[k] = 1 + level[head]
                    queue.append(k)

        return level


q = int(input())
for case in range(q):
    e = input().split()
    n = int(e[0])
    m = int(e[1])
    g=Graph()
    
    for edge in range(m):
        e = input().split()
        u = int(e[0])
        v = int(e[1])
        g.addEdge(u,v)

    s = int(input())
    distance = g.bfs(s, n)
    dist = []
    for i in distance[1:]:
        if i > 0:
            dist.append(str(i*6))
        if i < 0:
            dist.append(str(-1))

    print(" ".join(dist))
    #print("")