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;

#define vv vector< vector< int > >
#define ll long long


int main(){
    int n;
    cin >> n;
    vv tree(n);
    for(int i = 0; i < n; ++i){
        int a, k;
        cin >> a >> k;
        a--;
        for(int j = 0; j < k; ++j){
            int b;
            cin >> b;
            b--;
            tree[a].push_back(b);
        }
    }
    vector<int> dist(n, -1);
    queue<int> que;
    dist[0] = 0;
    que.push(0);

    while(!que.empty()){
        int v = que.front();
        que.pop();

        for (int nv : tree[v]){
            if(dist[nv] != -1) continue;
            dist[nv] = dist[v] + 1;
            que.push(nv);
        }
    }
    for(int v = 0; v < n; v++) cout << v+1 << " " << dist[v] << endl;
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
vector<int> graph[105];
bool vis[105];
int lvl[105];
int i;
void bfs(int rt)
{
    int src,adj;
    src=rt;
    deque<int>dq;
    vis[src]=1;
    lvl[src]=1;
    dq.push_back(src);
    while(!dq.empty())
    {
        src=dq.front();
        dq.pop_front();
        for(i=0; i<graph[src].size(); i++)
        {
            adj=graph[src][i];
            if(vis[adj]==0)
            {
                vis[adj]=1;
                lvl[adj]=lvl[src]+1;
                dq.push_back(adj);
            }
        }
    }
}
int main()
{
    int nodes,x,v;
    cin >> nodes;
    int u[200];
    memset(vis,0,sizeof(vis));
    memset(lvl,0,sizeof(lvl));
    for(i=1;i<=nodes;i++)
    {
        cin >> u[i];
        cin >> x;
        for(int j=0;j<x;j++)
        {
            cin >> v;
            graph[u[i]].push_back(v);
        }
    }
    bfs(1);
    for(i=1;i<=nodes;i++)
    {
        cout << u[i] << " " << lvl[u[i]]-1 << endl;
    }
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <cstdint>

using namespace std;

enum COLOR {
  WHITE,
  GRAY,
  BLACK,
};

static const int INFTY = INT_MAX;
static const int N = 100;

static int M[N][N] = {};
static vector<COLOR> color(N, WHITE);
static vector<int> d(N, INFTY);

static void bfs(int n, int s) {
  color[s] = GRAY;
  d[s] = 0;

  queue<int> Q;
  Q.push(s);

  while (!Q.empty()) {
    int u = Q.front();
    Q.pop();
    for (int v = 0; v < n; v++) {
      if (M[u][v] && color[v] == WHITE) {
          color[v] = GRAY;
          d[v] = d[u] + 1;
          Q.push(v);
      }
      color[u] = BLACK;
    }
  }
}

int main() {
  int n;
  cin >> n;

  int number, count, value;
  for (int i = 0; i < n; i++) {
    cin >> number >> count;
    number--;
    for (int j = 0; j < count; j++) {
     cin >> value;
     value--;
     M[number][value] = 1; 
    }
  }
  
  bfs(n, 0);
  
  for (int i = 0; i < n; i++) {
    cout << i + 1 << " " << ((d[i] == INFTY) ? -1 : d[i]) << endl; 
  }

  return 0;
}

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

struct VRTX {
	int v[100] = {}, dist = -1;
};

int n, curdist = 0;
VRTX u[100];

void breadthFirstSearch(int x, int dist);

int main() {
	int i, j, id, dim;
	
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> id >> dim;
		for (j = 0; j < dim; j++) {
			cin >> u[id].v[j];
		}
	}

	breadthFirstSearch(1, 0);

	for (i = 1; i <= n; i++) {
		cout << i << " " << u[i].dist << endl;
	}

	return 0;
}

void breadthFirstSearch(int x, int dist) {
	int i, nextdist;

	if (u[x].dist == -1)u[x].dist = dist;
	else u[x].dist = min(u[x].dist, dist);
	
	i = 0;
	nextdist = u[x].dist + 1;
	while (u[x].v[i] != 0) {
		breadthFirstSearch(u[x].v[i], nextdist);
		i++;
	}
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<bitset>
#include<vector>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<iomanip>
#include <functional>
using namespace std;
typedef long long ll;
const int mod = 1000000007;
const int INF = 1 << 28;
//cout << fixed << std::setprecision(9)
//memset(a, 0, sizeof(a));
//--------------------------

int n;
bool g[110][110];
int d[110];

void bfs(int s)
{
	d[s] = 0;
	queue<int> q;
	q.push(s);
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		for (int i = 1; i <= n; i++) {
			if (g[u][i] && d[i] == INF) {
				q.push(i);
				d[i] = d[u] + 1;
			}
		}
	}
}

int main()
{
	cin >> n;
	for (int i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			g[u][v] = true;
		}
	}

	for (int i = 1; i <= n; i++) d[i] = INF;

	bfs(0);

	for (int i = 1; i <= n; i++)
		cout << i << " " << d[i] << endl;

	return 0;
}

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

void calc(const vector<vector<int> >& G, vector<int>& D) {
    queue<int> Q;
    D[1] = 0;
    Q.push(1);
    while (!Q.empty()) {
        int i = Q.front();
        Q.pop();
        for (int j = 1; j < G[i].size(); j++) {
            if (G[i][j] && D[j] == -1) {
                D[j] = D[i] + 1;
                Q.push(j);
            }
        }
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<int> > G(n + 1, vector<int>(n + 1, 0));
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            G[u][v] = 1;
        }
    }
    vector<int> D(n + 1, -1);
    calc(G, D);

    for (int i = 1; i <= n; i++) {
        cout << i << " " << D[i] << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<queue>

using namespace std;
static const int N = 100;
static const int INFTY = (1<<21);

int n, M[N][N];
int d[N];

void bfs(int s) {
  queue<int> q;
  q.push(s);
  for (int i = 0; i < n; i++) {
    d[i] = INFTY;
  }
  d[s] = 0;
  int u;
  while (!q.empty()) {
    u = q.front(); q.pop();
    for (int v = 0; v < n; v++) {
      if (M[u][v] == 0) {
        continue;
      }
      if (d[v] != INFTY) {
        continue;
      }
      d[v] = d[u] + 1;
      q.push(v);
    }
  }
  for (int i = 0; i < n; i++) {
    cout << i + 1 << " " << ((d[i] == INFTY) ? (-1) : d[i]) << end;
  }
}

 int main()
{
  int u, k, v;

  cin >>n;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }

  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;
}