Problem:
Breadth First Search Write a program which reads an directed graph $G = (V, E)$, and finds the shortest distance from vertex $1$ to each vertex (the number of edges in the shortest path). Vertices are identified by IDs $1, 2, ... n$. Input In the first line, an integer $n$ denoting the number of vertices, is given. In the next $n$ lines, adjacent lists of vertex $u$ are given in the following format: $u$ $k$ $v_1$ $v_2$ ... $v_k$ $u$ is ID of the vertex and $k$ denotes its degree.$v_i$ are IDs of vertices adjacent to $u$. Constraints  $1 \leq n \leq 100$  Output For each vertex $u$, print $id$ and $d$ in a line. $id$ is ID of vertex $u$ and $d$ is the distance from vertex $1$ to vertex $u$. If there are no path from vertex $1$ to vertex $u$, print -1 as the shortest distance. Print in order of IDs. Sample Input 1 4
1 2 2 4
2 1 4
3 0
4 1 3 Sample Output 1 1 0
2 1
3 2
4 1 Reference Introduction to Algorithms, Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, and Clifford Stein. The MIT Press.

Solution (Python):
n = int(input())
 
adj = [None]
for i in range(n):
    adj_i = list(map(int, input().split()[2:]))
    adj.append(adj_i)
 
isSearched = [None] + [False] * n
 
distance = [None] + [-1] * n
 
def bfs(u):
    d = 0
    isSearched[u] = True
    distance[u] = d
    edge = [u]
    while edge:
        q = list(edge)
        edge = []
        d += 1
        for c_e in q:
            for n_e in adj[c_e]:
                if not isSearched[n_e]:
                    isSearched[n_e] = True
                    edge.append(n_e)
                    distance[n_e] = d
 
 
bfs(1)
 
for i, x in enumerate(distance[1:], start=1):
    print(i, x)

Solution (Python):


def BFS(adj, start):
    n = len(adj)
    d = [-1] * n
    flag = [0] * n
    Q = []

    Q.append(start)
    d[start] = 0
    flag[start] = 1

    while len(Q) != 0:
        u = Q.pop(0)
        v = [i for i, x in enumerate(adj[u]) if (x == 1) and (flag[i] == 0)] 
        
        for i in v:
            Q.append(i)
            d[i] = d[u] + 1
            flag[i] = 1
    
    return d

def main():
    n = int(input())
    adj = [[0 for i in range(n)] for j in range(n)]
    
    for i in range(n):
        tmp = list(map(int, input().split()))
        u = tmp[0]
        u = u -1
        k = tmp[1]
        v = tmp[2:]
        for j in range(k):
            adj[u][v[j]-1] = 1
    
    d = BFS(adj, 0)
    for i in range(n):
        print(i+1, d[i])


if __name__ == "__main__":
    main()

Solution (Python):
from sys import stdin
from collections import deque
n = int(stdin.readline())
M = [[0] * (n + 1) for _ in range(n + 1)]
d = [200] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque()
    dq.append(1)
    while len(dq) > 0:
        u = dq.popleft()
        for v in range(1, n + 1):
            if M[u][v] == 0 or d[v] != 200: continue
            d[v] = d[u] + 1
            dq.append(v)
    for i in range(1, n + 1):
        print(i, (-1 if d[i] == 200 else d[i]))
for u in range(1, n + 1):
    U = [int(j) for j in stdin.readline().split()]
    for v in U[2:]:
        M[u][v] = 1
bfs()

Solution (Python):
from sys import stdin
from collections import deque
n = int(stdin.readline())
d = [-1] * (n + 1)
def bfs(G):
    d[1] = 0
    queue = [1]
    dq = deque([1])
    while len(dq) > 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] < 0:
                d[c] = d[v] + 1
                dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = {}
for i in range(n):
    x = list(map(int, stdin.readline().split()))
    G[x[0]] = x[2:]
bfs(G)

Solution (Python):
from sys import stdin
from collections import deque
n = int(stdin.readline())
d = [-1] * (n + 1)
def bfs(G):
    d[1] = 0
    dq = deque([1])
    while len(dq) > 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] < 0:
                d[c] = d[v] + 1
                dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = [0]
for i in range(n):
    G.append(list(map(int, stdin.readline().split()[2:])))
bfs(G)

Solution (Python):
from sys import stdin
from collections import deque
n = int(stdin.readline())
d = [-1] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque([1])
    while len(dq) > 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] < 0:
                d[c] = d[v] + 1
                dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = [0] + [list(map(int, stdin.readline().split()[2:])) for i in range(n)]
bfs()

Solution (Python):
from sys import stdin
from collections import deque
n = int(stdin.readline())
d = [-1] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque([1])
    while len(dq) != 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] != -1 : continue
            d[c] = d[v] + 1
            dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = [0] + [list(map(int, stdin.readline().split()[2:])) for i in range(n)]
bfs()

Solution (Python):
from sys import stdin
from collections import deque
n = int(input())
d = [-1] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque([1])
    while len(dq) != 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] != -1 : continue
            d[c] = d[v] + 1
            dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = [0] + [list(map(int, input().split()[2:])) for i in range(n)]
bfs()

Solution (Python):
from sys import stdin
from collections import deque
n = int(input())
d = [-1] * (n + 1)
def bfs():
    d[1] = 0
    dq = deque([1])
    while len(dq) != 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] != -1 : continue
            d[c] = d[v] + 1
            dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
G = [0] + [list(map(int, input().split()[2:])) for _ in range(n)]
bfs()

Solution (Python):
from sys import stdin
from collections import deque
n = int(input())
d = [-1] * (n + 1)
G = [0] + [list(map(int, input().split()[2:])) for _ in range(n)]
def bfs():
    d[1] = 0
    dq = deque([1])
    while len(dq) != 0:
        v = dq.popleft()
        for c in G[v]:
            if d[c] == -1 :
                d[c] = d[v] + 1
                dq.append(c)
    for i, x in enumerate(d[1:], start=1):
        print(i, x)
bfs()

Solution (Python):
from sys import stdin
from collections import deque
n = int(input())
d = [-1] * (n + 1)
G = [0] + [list(map(int, input().split()[2:])) for _ in range(n)]
d[1] = 0
dq = deque([1])
while len(dq) != 0:
    v = dq.popleft()
    for c in G[v]:
        if d[c] == -1 :
            d[c] = d[v] + 1
            dq.append(c)
for i, x in enumerate(d[1:], start=1):
    print(i, x)

Solution (Python):
from sys import stdin
from collections import deque
n = int(input())
d = [-1] * (n + 1)
G = [0] + [list(map(int, input().split()[2:])) for _ in range(n)]
d[1] = 0
dq = deque([1])
while len(dq) != 0:
    v = dq.popleft()
    for c in G[v]:
        if d[c] == -1 :
            d[c] = d[v] + 1
            dq.append(c)
for i in range(1, n + 1):
    print(i, d[i])

Solution (Python):
from collections import deque
import sys


def bfs():
    color[0] = "GRAY"
    d[0] = 0
    Q.append(0)
    while len(Q) != 0:
        u = Q.popleft()
        for v in range(n):
            if M[u][v] and color[v] == "WHITE":
                color[v] = "GRAY"
                d[v] = d[u] + 1
                Q.append(v)
        color[u] = "BLACK"


if __name__ == "__main__":
    n = int(sys.stdin.readline())
    M = [[0] * n for i in range(n)]
    color = ["WHITE"] * n
    d = [-1] * n
    Q = deque()
    for inp in sys.stdin.readlines():
        inp = list(map(int, inp.split()))
        for i in inp[2:]:
            M[inp[0]-1][i-1] = 1
    bfs()
    for i in range(n):
        print(i+1, d[i])

Solution (Python):
import sys
import Queue

d_num = int(sys.stdin.readline().strip())

graph_list = []

for _ in range(0, d_num):
    array = sys.stdin.readline().strip().split(" ")
    if len(array) <= 2:
        graph_list.append([])
    else:
        graph_list.append([int(array[i]) - 1 for i in range(2, len(array))])

result = [0 for _ in range(0, d_num)]
searched_list = []
queue = Queue.Queue()

queue.put((0, 0))
searched_list.append(0)
while not queue.empty():
    data = queue.get()
    node = data[0]
    d = data[1]
    children = filter(lambda x: x not in searched_list, graph_list[node])
    for c in children:
        queue.put((c, d + 1))
        searched_list.append(c)
        result[c] = d + 1

for i in range(0, len(result)):
    if (i != 0) and (result[i] == 0):
        print str(i + 1) + " " + str(-1)
    else:
        print str(i + 1) + " " + str(result[i])

Solution (Python):
from collections import deque

INF = 1e9

def BFS(n, adj):
    d = [INF] * N
    d[0] = 0
    next_v = deque([0]) 
    
    while next_v:
        u = next_v.popleft()
        
        for v in adj[u]:
            if d[v] == INF:
                d[v] = d[u] + 1
                next_v.append(v)
    
    return d

N = int(input())
Adj = [None] * N

for i in range(N):
    u, k, *vertex = [int(i)-1 for i in input().split()]
    Adj[u] = vertex

distance = BFS(N, Adj)

for i, di in enumerate(distance, start = 1):
    if di == INF:
        print(i, -1)
    else:
        print(i, di)

Solution (Python):

from collections import deque

N = int(input())
adj = [[0]*N for _ in range(N)]
unsearched = set(range(1, N))
result = {n:-1 for n in range(N)}

for n in range(N):
    inp = list(map(int, input().split()))
    for i in inp[2:]:
        adj[inp[0]-1][i-1] = 1

que = deque([[0, 0]]) 


while len(que):
    q = que.pop()
    result[q[0]] = q[1]
    next_ = [[i, q[1] + 1] for i, a in enumerate(adj[q[0]]) if (a==1) & (i in unsearched)]
    unsearched = unsearched.difference([i[0] for i in next_])
    que.extendleft(next_)

for n in range(N):
    print("{} {}".format(n+1, result[n]))

Solution (Python):
n = int(input())
graph = {}
d = [-1] * (n+1)
for i in range(n):
    t = list(map(int, input().split()))
    v = t[0]
    k = t[1]
    graph[v] = [t[i+2] for i in range(k)]

from queue import Queue

def bfs(s):
    d[s] = 0
    q=Queue()
    q.put(s)
    while not q.empty():
        v=q.get()
        for child in graph[v]:
            if d[child] != -1: continue
            d[child] = d[v] + 1
            q.put(child)
bfs(1)
for i in range(1, n+1):print(i,d[i])

Solution (Python):
class Queue:
  def __init__(self,c):
    self.values = [None]*(c+1)
    self.s = 0
    self.t = 0

  def push(self,x):
    if self._next(self.s) == self.t:
      raise Exception("Overflow")
    self.values[self.s] = x
    self.s = self._next(self.s)

  def pop(self):
    if self.s == self.t:
      raise Exception("Underflow")
    ret = self.values[self.t]
    self.t = self._next(self.t)
    return ret

  def size(self):
    if self.s >= self.t:
      return self.s-self.t
    else:
      return len(self.values) - (self.t-self.s)


  def _next(self,p):
    p += 1
    if p >= len(self.values):
      p = 0
    return p


def solve(G):
  d = {}
  n = len(G)
  for u in G:
    d[u] = -1
  d[1] = 0
  queue = Queue(n+1)
  queue.push(1)
  while queue.size() > 0:
    u = queue.pop()
    for v in G[u]:
      if d[v] == -1:
        d[v] = d[u] + 1
        queue.push(v)
  return d







n = int(input())
G = {}
for i in range(n):
  entry = list(map(int, input().split(' ')))
  u = entry[0]
  k = entry[1]
  G[u] = set()
  for v in entry[2:]:
    G[u].add(v)


d = solve(G)
for u in G:
  print(u,d[u])

Solution (Python):

n=int(input())
V=[]
a=[1]
for i in range(n):
    V.append([int(i) for i in input().split()])
    a.append(0)
V=sorted(V,key=lambda x:x[0])
print('1 0')
d=1
c=0
w=[0]
p=[]
while c<n and w!=[]:
    i=0
    y=[]
 
    while c<n and i<len(w):
        j=2
        while j<2+V[w[i]][1] and c<n:
            if a[V[w[i]][j]-1]==0:
        
                a[V[w[i]][j]-1]=1
                p.append([V[w[i]][j],d])
                c+=1
                y.append(V[w[i]][j]-1)
            j+=1
        i+=1
    w=y
    d+=1
p=sorted(p, key=lambda x:x[0])

i=2
j=0
while i <=n and j<len(p):
    while p[j][0]>i:
        print(str(i) +" -1")
        i+=1
    print(str(p[j][0])+" "+str(p[j][1]))
    i+=1
    j+=1
while i<=n:
    print(str(i)+" -1")
    i+=1

Solution (Python):
def srch(i, l, Lng, Dst):
    if Lng[i] != -1 and Lng[i] < l:
        return
    Lng[i] = l
    if Dst[i] is not None and len(Dst[i]) > 0:
        for c in Dst[i]:
            srch(c,l+1, Lng, Dst)

def main():
    num = int(input())
    Dst = [None for i in range(num + 1)]
    Lng = [-1] * (num + 1)
    
    for n in range(1, num+1):
        a = list(map(int,input().split()))
        u = a[0]
        if a[1] > 0:
            Dst[u] = a[2:]

    srch(1, 0, Lng, Dst)

    for n in range(1, num+1):
        l = Lng[n]
        if l > num:
            l = -1
        print("{} {}".format(n,l))

if __name__ == '__main__':
    main()

Solution (Python):
def main():
    n = input()
    A = []
    for i in xrange(n):
        A.append(map(int,raw_input().split()))

    c,d = bfs(n,A)

    for i in xrange(n):
        if c[i] == -1:
            print i+1, -1
        else:
            print i+1, d[i]

def bfs(n,A):
    color = [-1]*n
    d = [-1]*n
    Q = []
    d[0] = 0
    Q.append(0)
    while(True):
        if len(Q)==0:
            break
        u = Q.pop(0)
        for i in A[u][2:]:
            if color[i-1] == -1:
                color[i-1] = 0
                d[i-1] = d[u]+1
                Q.append(i-1)
        color[u] = 1
    return color, d    

if __name__ == '__main__':
    main()

Solution (Python):
from collections import deque
N = input()
d = [float('inf')] * N
m = [[0] * N for i in range(N)]
Q = deque([])

def bfs(s):
    Q.append(s)
    d[s] = 0

    while(len(Q) != 0):
        u = Q.popleft()
        for v in range(N):
            if (m[u][v] and  d[v] == float('inf')):
                d[v] = d[u] + 1
                Q.append(v)




if __name__ == '__main__':

    for i in range(N):
        v = map(int, raw_input().split())
        for j in v[2:]:
            m[i][j-1] = 1
    
    bfs(0)

    for i in range(N):
        if d[i] == float('inf'):
            d[i] = -1
        print (i+1), d[i]

Solution (Python):
from collections import deque
N = input()
d = [float('inf')] * N
m = [[] for i in xrange(N)]
Q = deque([])

def bfs(s):
    Q.append(s)
    d[s] = 0

    while(len(Q) != 0):
        u = Q.popleft()
        for v in m[u]:
            if( d[v] == float('inf')):
                d[v] = d[u] + 1
                Q.append(v)

if __name__ == '__main__':

    for i in range(N):
        v = map(int, raw_input().split())
        for j in v[2:]:
            m[i].append(j-1)
    
    bfs(0)

    for i in range(N):
        if d[i] == float('inf'):
            d[i] = -1
        print (i+1), d[i]

Solution (Python):
n = int(input())

G = []
G.append([])
for i in range(n):
    v = list(map(int, input().split()))
    G.append(v[2:])

q = []
q.append(1)

checked = [False] * (n + 1)
checked[1] = True
d = [-1] * (n + 1)
d[1] = 0

while q:
    current = q.pop(0)
    for v in G[current]:
        if not checked[v]:
            q.append(v)
            d[v] = d[current] + 1
            checked[v] = True

for i in range(1, n + 1):
    print(i, d[i])

Solution (Python):
from sys import stdin
from collections import deque

n = int(stdin.readline())
g = [None] * n
for _ in range(n):
    u, _, *cs = [int(s) for s in stdin.readline().split()]
    g[u-1] = [c - 1 for c in cs]
ds = [-1] * n
v = [False] * n
v[0] = True
q = deque([(0, 0)])
while len(q):
    u, d = q.popleft()
    ds[u] = d
    for c in g[u]:
        if not v[c]:
            v[c] = True
            q.append((c, d + 1))
for u, d in enumerate(ds):
    print(u + 1, d)

Solution (Python):
from collections import defaultdict
v_num = int(input())
connect = defaultdict(list)
for v in range(v_num):
    inp = [int(n) - 1 for n in input().split(" ")]
    connect[inp[0]].extend(inp[2:])
answer = [[m + 1, -1] for m in range(v_num)]
queue = [0]
visited = [0 for n in range(v_num)]
visited[0] = 1
time = 0
while queue:
    new_queue = []
    for q in queue:
        answer[q][1] = time
        for c in connect[q]:
            if not visited[c]:
                visited[c] = 1
                new_queue.append(c)
    queue = new_queue
    time += 1
for v in range(v_num):
    print(*answer[v])

Solution (Python):
def bfs(graph, start, result):
    visited = {start: None}
    unvisited = [start]
    while unvisited:
        now = unvisited[0]
        unvisited = unvisited[1:]
        if visited[now] == None:
            result[now] = 0
        else:
            result[now] = result[visited[now]] + 1
        for next in graph[now][2:]:
            if not (next in visited):
                unvisited.append(next)
                visited[next] = now
    return visited

n = int(input())
g = [[]]
r = {i: -1 for i in range(n + 1)}

for i in range(n):
    g.append(list(map(int, input().split())))

v = bfs(g, 1, r)

for i in range(1,n+1):
    print(i, r[i])

Solution (Python):
import collections

n=int(input())
adj=[]
for i in range(n):
      adj.append(list(map(int, input().split())))

Q=[]
Q=collections.deque()
Q.append(0)

D=[-1 for i in range(n)]
D[0]=0

while len(Q)>0:
    current=Q.popleft()
    for dst in range(n):
        for i in range(2,len(adj[current])):
            if adj[current][i]==dst+1 and D[dst]==-1:
                D[dst]=D[current]+1
                Q.append(dst)
for i in range(n):
    print(i+1,D[i])

Solution (Python):
from collections import deque
def bfs(s):
    color[s] = 'GRAY'
    d[s] = 0
    Q.append(0)
    while len(Q) != 0:
        u = Q.popleft()
        for v in range(n):
            if M[u][v] and color[v] == 'WHITE':
                color[v] = 'GRAY'
                d[v] = d[u] + 1
                Q.append(v)
        color[u] = 'BLACK'
        
n = int(input())
M = [[0] * n for _ in range(n)]
color = ['WHITE'] * n
d = [-1] * n
Q = deque()

for _ in range(n):
    a = list(map(int, input().split()))
    u = a[0]
    v = a[2:]
    for j in v:
        M[u - 1][j - 1] = 1
        
bfs(0)

for i in range(n):
    out = ''
    out += '{} {}'.format(i + 1, d[i])
    print(out)

Solution (Python):
n = int(input())
a = [[] for i in range(n)]

for i in range(n):
    v = list(map(int, input().split()))
    u = v[0] - 1
    for j in v[2:]:
        a[u].append(j-1)

d = [-1] * n
isDiscovered = [False] * n

def bfs(x):
    for i in a[x]:
        if not isDiscovered[i]:
            isDiscovered [i] = True
            d[i] = d[x] + 1

d_ = 0
isDiscovered [0] = True
d[0] = 0
bfs(0)

flag = True
while flag:
    flag = False
    for i in range(n):
        if d[i] is d_ :
            flag = True
            bfs(i)
    d_ += 1

for i in range(n):
    print(i+1, d[i])

Solution (Python):
from sys import stdin

def bfs(graph,start,d):
    queue = [start]
    explored = []

    while len(queue) > 0:
        node = queue.pop(0)

        if node not in explored:
            neighbours = graph[node]
            for neighbour in neighbours:
                if neighbour not in queue:
                    
                    if d[neighbour-1] == -1:
                        d[neighbour - 1] = d[node - 1] + 1
                        queue.append(neighbour)
                        

            explored.append(node)

        
        


def main():
    n = int(stdin.readline())

    graph_dict = {}

    d = [-1]*n

    for i in xrange(n):
        entry = [int(s) for s in stdin.readline().split()[2:]]
        graph_dict[i+1] = entry

    d[0] = 0
    bfs(graph_dict,1,d)

    for i in xrange(n):
        print str(i+1) + ' ' + str(d[i])

main()

Solution (Python):

from collections import deque
n = int(input())
link = [[] for i in range(n+1)]
for i in range(n):
  r = list(map(int,input().split()))
  u = r.pop(0)
  k = r.pop(0)
  link[u] = r

searched=set()
queue = deque()
d = [-1 for i in range(n+1)]

v = 1
d[v] = 0
queue.append(v)
searched.add(v)
while queue:
  v = queue.popleft()
  for w in link[v]:
    if w not in searched:
      d[w] = d[v] + 1
      queue.append(w)
      searched.add(w)

for i in range(1,n+1):
  print(str(i) + " " + str(d[i]))

Solution (Python):

from collections import deque


if __name__ == '__main__':

    n = int(input())
    M = [[0 for i in range(n)] for j in range(n)]
    for _ in range(n):
        l = list(map(int, input().split(" ")))
        u = l[0]
        k = l[1]
        if k != 0:
            for v in l[2:]:
                M[u - 1][v - 1] = 1

    color = [0] * n
    d = [-1] * n
    Q = deque()

    def bfs(s):  
        color[s] = 1
        d[s] = 0
        Q.append(s)

        while len(Q) != 0:
            u = Q.popleft()
            for v in range(n):
                if M[u][v] == 1 and color[v] == 0:
                    color[v] = 1
                    d[v] = d[u] + 1
                    Q.append(v)
            color[u] = 2

    bfs(0)
    for i in range(n):
        print(i + 1, d[i])

Solution (Python):
from collections import deque
def MAIN():
    n = int(input())
    li = [[] for _ in range(n + 1)]
    ans = [[i, -1] for i in range(n + 1)]
    ans[1][1] = 0
    for _ in range(n):
        u, k, *v = map(int, input().split())
        li[u] = v
    dp = deque([1])
    while dp:
        u = dp.popleft()
        for v in li[u]:
            if ans[v][1] == -1:
                ans[v][1] = ans[u][1] + 1
                dp.append(v)
    for d in ans[1:]:
        print(*d)
MAIN()

Solution (Python):
import queue
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
N=int(input())
M=[list(map(int,input().split()[2:]))for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v-=1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
N=int(input())
M=[list(map(int,input().split()[2:]))for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v-=1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue,sys
N=int(input())
M=[list(map(int,e.split()[2:]))for e in sys.stdin]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v-=1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue,sys
N=int(input())
M=[list(map(int,e.split()[2:]))for e in sys.stdin]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while q.qsize()>0:
 u=q.get()
 for v in M[u]:
  v-=1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while not q.empty():
 u=q.get()
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=queue.Queue();q.put(0)
d=[-1]*N;d[0]=0
while not q.empty():
 u=q.get()
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q.put(v)
for i in range(N):print(i+1,d[i])

Solution (Python):
import queue
def s():
 N=int(input())
 M=[input().split()[2:]for _ in[0]*N]
 q=queue.Queue();q.put(0)
 d=[-1]*N;d[0]=0
 while not q.empty():
  u=q.get()
  for v in M[u]:
   v=int(v)-1
   if d[v]<0:d[v]=d[u]+1;q.put(v)
 for i in range(N):print(i+1,d[i])
if'__main__'==__name__:s()

Solution (Python):
import queue
def s():
 N=int(input())
 M=[input().split()[2:]for _ in[0]*N]
 q=queue.Queue();q.put(0)
 d=[-1]*N;d[0]=0
 while not q.empty():
  u=q.get()
  for v in M[u]:
   v=int(v)-1
   if d[v]<0:d[v]=d[u]+1;q.put(v)
 for i in range(N):print(i+1,d[i])
if'__main__'==__name__:s()

Solution (Python):
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=[0]
d=[-1]*N;d[0]=0
while q:
 u=q.pop(0)
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q+=[v]
for i in range(N):print(i+1,d[i])

Solution (Python):
N=int(input())
M=[input().split()[2:]for _ in[0]*N]
q=[0]
d=[0]+[-1]*N
while q:
 u=q.pop(0)
 for v in M[u]:
  v=int(v)-1
  if d[v]<0:d[v]=d[u]+1;q+=[v]
for i in range(N):print(i+1,d[i])

Solution (Python):
from collections import deque

class Vertex:
    _id = -1
    _children = []
    _depth = -1

    def __init__(self, i, c):
        self._id = i
        self._children = c

    def getId(self):
        return self._id

    def getChildren(self):
        return self._children

    def getDepth(self):
        return self._depth

    def setDepth(self, d):
        self._depth = d

    def print(self):
        print("{} {}".format(self._id, self._depth))


n = int(input())
graph = [0 for i in range(n)]
queue = deque([])


for i in range(n):
    u = list(map(int, input().split(' ')))
    adj = []
    if u[1] > 0:
        adj = u[2:u[1]+2]
    graph[u[0]-1] = Vertex(u[0], adj)


graph[0].setDepth(0)
queue.append(graph[0])
while queue:
    v = queue.popleft()
    for u_id in v.getChildren():
        u = graph[u_id-1]
        if u.getDepth() == -1:
            u.setDepth(v.getDepth()+1)
            queue.append(u)


for v in graph:
    v.print()

Solution (Python):
from collections import deque

n = int(input())
adj = [list(map(int, input().split(' '))) for i in range(n)]

class Node:
  def __init__(self, id, ck):
    self.id = id
    self.ck = ck
    self.depth = -1

  def __str__(self):
    return '{} {}'.format(self.id, self.depth)

class Graph:
  def __init__(self):
    self.map = {}

  def get(self, id):
    return self.map[id]

  def set(self, id, ck):
    self.map[id] = Node(id, ck)

  def bfs(self):
    root = self.get(1)
    root.depth = 0
    queue = deque()
    queue.append(root)
    while(len(queue) > 0):
      node = queue.popleft()
      for id in node.ck:
        target = self.get(id)
        if target.depth != -1: continue
        target.depth = node.depth + 1
        queue.append(target)

  def __str__(self):
    return '\n'.join(map(str, [self.get(i + 1) for i in range(len(self.map))]))

graph = Graph()
for data in adj:
  id = data[0]
  ck = data[2:]
  graph.set(id, ck)

graph.bfs()
print(graph)

Solution (Python):
n = int(input())

m = [[0 for i in range(n)] for j in range(n)]

for i in range(n):
    com = list(map(int, input().split()))
    for j in range(com[1]):
        m[i][com[j+2]-1] = 1

color = ["white" for i in range(n)]

from collections import deque
queue = deque()

d = [-1 for i in range(n)]

def bfs():
    color[0] = "gray"
    d[0] = 0
    queue.append(0)
    while len(queue) != 0:
        u = queue.popleft()
        for i in range(n):
            if m[u][i] and color[i] == "white":
                color[i] = "gray"
                d[i] = d[u] + 1
                queue.append(i)
        color[u] = "black"

bfs()
for i in range(n):
    print(i+1, d[i])

Solution (Python):
from collections import deque
from enum import Enum, auto

class Color(Enum):
    WHITE = auto()
    GRAY = auto()
    BLACK = auto()

n = int(input())
d = [0 for i in range(n)]
f = [0 for i in range(n)]

colors = [] 
A = [[0 for j in range(n)] for i in range(n)] 
queue = deque([])


for i in range(n):
    arr = list(map(int, input().split(' ')))
    u, k, v = arr[0], arr[1], arr[2:]
    for j in range(k):
        A[u-1][v[j]-1] = 1

def bfs():
    global colors, queue, d
    colors = [Color.WHITE for i in range(n)]
    d = [-1 for i in range(n)] 

    colors[0] = Color.GRAY
    d[0] = 0
    queue.append(0)

    while len(queue) > 0:
        u = queue.popleft()
        for v in range(n):
            if A[u][v] == 1 and colors[v] == Color.WHITE:
                colors[v] = Color.GRAY
                d[v] = d[u] + 1
                queue.append(v)
        colors[u] = Color.BLACK

bfs()

for i in range(n):
    print(i+1, d[i])