Go: package main

import (
	"container/list"
	"fmt"
	"bufio"
	"os"
	"strconv"
)

const (
	N   = 100
	INF = 1 << 21
)

var (
	n        int
	adj      [N][N]int
	distance [N]int
)

func BFS(start int) {
	q := list.New()
	q.PushBack(start)
	for i := 0; i < n; i++ {
		distance[i] = INF
	}
	distance[start] = 0
	u := 0
	for q.Len() != 0 {
		u = q.Remove(q.Front()).(int)
		for v := 0; v < n; v++ {
			if adj[u][v] == 0 {
				continue
			}
			if distance[v] != INF {
				continue
			}
			distance[v] = distance[u] + 1
			q.PushBack(v)
		}
	}
	for i := 0; i < n; i++ {
		var d int
		if distance[i] == INF {
			d = -1
		} else {
			d = distance[i]
		}
		fmt.Printf("%d %d\n", i+1, d)
	}
}

func main() {
	var u, k, v int
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ = strconv.Atoi(scanner.Text())
		u -= 1
		scanner.Scan()
		k, _ = strconv.Atoi(scanner.Text())
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ = strconv.Atoi(scanner.Text())
			v -= 1
			adj[u][v] = 1
		}
	}
	BFS(0)
}

C++: #include <bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;
//const int mod = 998244353;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}

template< typename T = int >
struct Edge {
  int from, to;
  T cost;
  int idx;

  Edge() = default;

  Edge(int from, int to, T cost = 1, int idx = -1) : from(from), to(to), cost(cost), idx(idx) {}

  operator int() const { return to; }
};

template< typename T = int >
struct Graph {
  vector< vector< Edge< T > > > g;
  int es;

  Graph() = default;

  explicit Graph(int n) : g(n), es(0) {}

  size_t size() const {
    return g.size();
  }

  void add_directed_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es++);
  }

  void add_edge(int from, int to, T cost = 1) {
    g[from].emplace_back(from, to, cost, es);
    g[to].emplace_back(to, from, cost, es++);
  }

  void read(int M, int padding = -1, bool weighted = false, bool directed = false) {
    for(int i = 0; i < M; i++) {
      int a, b;
      cin >> a >> b;
      a += padding;
      b += padding;
      T c = T(1);
      if(weighted) cin >> c;
      if(directed) add_directed_edge(a, b, c);
      else add_edge(a, b, c);
    }
  }
};

template< typename T = int >
using Edges = vector< Edge< T > >;


/**
 * @brief BFS(単一始点最短路)
 */
template< typename T >
vector< T > bfs(const Graph< T > &g, int s) {
  T max_cost = 0, beet = 0;
  for(auto &es : g.g) {
    for(auto &e : es) max_cost = max(max_cost, e.cost);
  }
  ++max_cost;
  const auto INF = numeric_limits< T >::max();
  vector< T > dist(g.size(), INF);
  vector< queue< int > > ques(max_cost + 1);
  dist[s] = 0;
  ques[0].emplace(s);
  for(T cost = 0; cost <= beet; cost++) {
    auto &que = ques[cost % max_cost];
    while(!que.empty()) {
      int idx = que.front();
      que.pop();
      if(dist[idx] < cost) continue;
      for(auto &e : g.g[idx]) {
        auto next_cost = cost + e.cost;
        if(dist[e.to] <= next_cost) continue;;
        dist[e.to] = next_cost;
        beet = max(beet, dist[e.to]);
        ques[dist[e.to] % max_cost].emplace(e.to);
      }
    }
  }
  return dist;
}


int main() {
  int N, X, Y;
  cin >> N;
  Graph<> g(N);
  for(int i = 0; i < N; i++) {
    int U, K;
    cin >> U >> K;
    --U;
    for(int j = 0; j < K; j++) {
      int x;
      cin >> x;
      --x;
      g.add_directed_edge(U, x);
    }
  }
  auto d = bfs(g, 0);
  for(int i = 0; i < N; i++) {
    cout << i + 1 << " ";
    if(d[i] == numeric_limits< int >::max()) cout << -1 << "\n";
    else cout << d[i] << "\n";
  }
}

C++: #include<iostream>
#include<cstring>
#include<queue>
using namespace std;

#define N 100
#define INFTY (1<<30)
int n,m[N][N],d[N];//通过距离管理访问状态(color)

void bfs(int s) //广搜
{
    queue<int> q;
    q.push(s);
    for(int i=0;i<n;i++) d[i]=INFTY; //注意这里不能用memset
    d[s]=0; //初始化

    while(!q.empty())
    {
        int u=q.front();q.pop();
        for(int v=0;v<n;v++)
        {
            if(m[u][v]&&d[v]==INFTY) //如果有节点与u相邻且该节点没有被访问过
            {
                d[v]=d[u]+1; //距离+1
                q.push(v); //将该节点加入待访问队列中
            }
        }
    }

    for(int i=0;i<n;i++)
        cout<<i+1<<" "<<(d[i]==INFTY ? -1 : d[i])<<endl; //注意这里要用括号
}

int main()
{
    int u,k,v;
    cin>>n;
    for(int i=0;i<n;i++)
    {
        cin>>u>>k;
        u--;
        for(int j=0;j<k;j++)
        {
            cin>>v;
            v--;
            m[u][v]=1;
        }
    }
    bfs(0);
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int main()
{
int n,u,k,v;scanf("%d",&n);
vector<vector<int>> G(n);
for(int i=0;i<n;i++)
{
scanf("%d %d",&u,&k);
for(int j=0;j<k;j++)
{
scanf("%d",&v);
G[u-1].push_back(v-1);
}
}
vector<int> dis(n,-1);
queue<int> que;
dis[0]=0;
que.push(0);
while(!que.empty())
{
v=que.front();
que.pop();
for(int nv : G[v])
{
if(dis[nv]!=-1)continue;
dis[nv]=dis[v]+1;
que.push(nv);
}
}
for(int i=0;i<n;i++)printf("%d %d\n",i+1,dis[i]);
}