Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type AdjacentList struct {
	matrix [][]int
}

func NewEmptyAdjacentList(dim int) *AdjacentList {
	matrix := make([][]int, dim)
	for i := 0; i < dim; i++ {
		matrix[i] = make([]int, dim)
	}
	return &AdjacentList{matrix: matrix}
}

func (al *AdjacentList) set(node int, adjacent int) {
	al.matrix[node-1][adjacent-1] = 1
}

func (al *AdjacentList) findAdjacentsFor(node int) []int {
	adjacents := []int{}
	for i, v := range al.matrix[node-1] {
		if v == 1 {
			adjacents = append(adjacents, i+1)
		}
	}
	return adjacents
}

type DistanceList struct {
	list []int
}

func NewDistanceList(dim int) *DistanceList {
	list := make([]int, dim)
	for i := 0; i < dim; i++ {
		list[i] = -1
	}
	return &DistanceList{list: list}
}

func (dl *DistanceList) set(node int, distance int) {
	dl.list[node-1] = distance
}

func (dl *DistanceList) get(node int) int {
	return dl.list[node-1]
}

func (dl *DistanceList) isVisited(node int) bool {
	return dl.list[node-1] >= 0
}

type Position struct {
	node     int
	distance int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	dim, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	al := NewEmptyAdjacentList(dim)

	for i := 1; i <= dim; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}

		adjacentNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		for j := 0; j < adjacentNum; j++ {
			adjacent, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			al.set(node, adjacent)
		}
	}

	dl := NewDistanceList(dim)

	bfs(al, dl)

	for i := 1; i <= dim; i++ {
		fmt.Printf("%d %d\n", i, dl.get(i))
	}
}

func bfs(al *AdjacentList, dl *DistanceList) {
	stack := []Position{Position{node: 1, distance: 0}}
	for len(stack) > 0 {
		currentPosition := stack[0]
		stack = stack[1:]
		if !dl.isVisited(currentPosition.node) {
			dl.set(currentPosition.node, currentPosition.distance)
		}
		for _, v := range al.findAdjacentsFor(currentPosition.node) {
			if !dl.isVisited(v) {
				stack = append(stack, Position{node: v, distance: currentPosition.distance + 1})
			}
		}
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

Python: n = int(input())

m = [[0 for _ in range(n+1)] for _ in range(n+1)]
mm = [[] for _ in range(n+1)]

for _ in range(n):
	tmp = [int(x) for x in input().split()]
	u,k,l = tmp[0],tmp[1],tmp[2:]
	mm[u] += tmp[2:]
	for x in l:
		m[u][x] = 1
		
dp = [float('inf') for _ in range(n+1)]
dp[1] = 0
queue = [1]

while queue:
	t = queue.pop(0)
	for x in mm[t]:
		if dp[x] > dp[t] + 1:
			dp[x] = dp[t] + 1
			queue.append(x)
		else:
			pass
			
for i,x in enumerate(queue):
	if i == 0:
		pass
	else:
		if x == float('inf'):
			print(i, -1)
		else:
			print(i, x)

Python: def BFS(G):
    ans = [0] + [[i+1,-1] for i in range(len(G))]
    def main(G,i,d):
        if -1 < ans[i][1] <= d: return
        ans[i] = [i, d]
        for j in G[i-1][2:]: main(G,j,d+1)
    main(G,1,0)
    return ans[1:]


if __name__=='__main__':
    n = int(input())
    G = [list(map(int,input().split())) for _ in range(n)]
    for out in BFS(G): print(*out)

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)

Python: n = int(input())

class Node:
    def __init__(self, idd, neighbors):
        self.idd = idd
        self.neighbors = neighbors
        self.dist = -1
        
    def __repr__(self):
        return "{0} {1}".format(self.idd, self.dist)
    
def breadthFirstSearch(Nodes):
    stack = [Nodes[0]]
    Nodes[0].dist = 0
    while len(stack) > 0:
        current = stack.pop(0)
        for v in current.neighbors:
            v_node = Nodes[v-1]
#             print('current:{}, v_node:{}'.format(current, v_node))
            if(v_node.dist == -1):
                v_node.dist = current.dist + 1
                stack.append(v_node)
            else:
                v_node.dist = v_node.dist if v_node.dist < current.dist + 1 else current.dist + 1
    return Nodes

Nodes = [None] * n
for i in range(n):
    row = [int(tt) for tt in input().split()]
    Nodes[row[0]-1] = Node(row[0], [ row[j + 2] for j in range(row[1])])

Nodes = breadthFirstSearch(Nodes)
for node in Nodes:
    print(node)

Python: from collections import deque


def get_next_node(node, discovery_time, adj_mat):
    for i, node in enumerate(adj_mat[node]):
        if discovery_time[i] == 0 and node == 1:
            return i
    return None

def bfs(node, adj_mat):
    distances = [-1] * len(adj_mat)

    distances[node] = 0
    q = deque(maxlen=len(adj_mat))
    q.append(0)
    while q:
        visit_node = q.popleft()
        for j in range(len(adj_mat)):
            if adj_mat[visit_node][j] and distances[j]==-1:
                distances[j] = distances[visit_node] + 1
                q.append(j)
    
    for i, d in enumerate(distances):
        print(i+1, d)


if __name__ == "__main__":
    n_node = int(input())
    # f = open('alds1_11_c-input.txt', 'r')
    # n_node = int(f.readline())

    adjacency_mat = [[0 for i in range(n_node)] for j in range(n_node)]
    for i in range(n_node):
        command = list(map(int, input().split()))
        # command = list(map(int, f.readline().split()))

        i = command.pop(0) - 1
        n_edge = command.pop(0)

        for j in command:
            adjacency_mat[i][j-1] = 1

    # f.close()
    discovery_time = [0] * n_node
    finish_time = [0] * n_node
    bfs(0, adjacency_mat)

Python: import collections

N = int(input())
route = []
for i in range(N):
    a = list(map(int, input().split()))
    route.append(a[2:])
ans = [-1 for _ in range(N)]
ans[0] = 0
check = collections.deque([0])#now distance
while check:
    now = check.popleft()
    for next in route[now]:
        next -= 1
        if ans[next] == -1:
            check.append(next)
            ans[next] = ans[now]+1
for i in range(N):
    print(i+1, ans[i])

Python: N= int(input())
E = [input().split()[2:] for _ in range(N)]
Q = [0]
L = [0] + [-1]*N
flag = [1] + [0]*N
def func(ide):
    global Q
    for i in E[ide]:
        i = int(i) - 1
        if frag[i] != 1:frag[i] = 1;L[i] = L[ide] +1 ;Q.append(i)
    

while Q:top = Q.pop(0);func(top)

for i in range(N):print(i + 1 ,int(L[i]))

Python: from collections import deque
from enum import Enum

class Color(Enum):
  WHITE = 0
  GRAY = 1
  BLACK = 2


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


colors = [Color.WHITE for i in range(N)]
INF = N
d = [-1 for i in range(N)]
d[0] = 0

q = deque()
q.append(1)
colors[0] == Color.GRAY
while len(q) > 0:
  u = q.popleft()-1
  for v in adj[u]:
    v -= 1
    if colors[v] != Color.WHITE:
      continue
    d[v] = d[u] + 1
    colors[v] = Color.GRAY
    q.append(v+1)
  colors[u] = Color.BLACK

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

Python: N= int(input())
frag, T, L,Q = [0]*N, [0]*N, [0]*N, [0]
a,frag[0] = 100, 1
def func(ide):
    for i in E[ide]:
        i = int(i) - 1
        if frag[i] != 1:frag[i] = 1;L[i] = L[ide] +1 ;Q.append(i) 
        else:return
E = [input().split()[2:] for _ in range(N)]

while Q:top = Q[0];func(top);del Q[0]
    
for i in range(N):print(i + 1 ,int(L[i]))