Go: package main

import "fmt"

type container struct {
	data []int
}

func (c *container) queue(v int) {
	c.data = append(c.data, v)
}
func (c *container) dequeue(p *int) bool {
	if p == nil || len(c.data) == 0 {
		return false
	}
	*p = c.data[0]
	c.data = c.data[1:len(c.data)]
	return true
}

func main() {
	var n int
	fmt.Scan(&n)
	g := make([][]int, n+1) // 1-indexed
	d := make([]int, n+1)   // 1-indexed
	for i := 1; i <= n; i++ {
		d[i] = -1
		var u, k, v int
		fmt.Scan(&u, &k)
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			g[u] = append(g[u], v)
		}
	}

	var q container
	d[1] = 0
	q.queue(1)

for len(q.data) > 0  { // 幅優先探索
		var v int
		q.dequeue(&v)
		for i := 0; i < len(g[v]); i++ {
			nv := g[v][i]
		if d[nv] == -1 { // 未訪問
				q.queue(nv)
				d[nv] = d[v] + 1
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d\n", i, d[i])
	}
}

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

struct Tree
{
    int p, start, end, min;
    bool isSearched;
    vector<int> v;
};

void DFS( Tree* t, int a, int cnt )
{
    if( t[a].isSearched && t[a].min <= cnt )
        return;
    
    t[a].isSearched = true;

    if( t[a].min > cnt )
        t[a].min = cnt;

    cnt++;

    for( int i = 0; i < t[a].v.size(); i++ )
        DFS( t, t[a].v[i], cnt );
}


int main()
{
    int n, a, b, c;
    Tree t[101];

    for( int i = 0; i < 101; i++ )
    {
        t[i].p = -1;
        t[i].min = 1000;
        t[i].isSearched = false;
    }
    
    cin >> n;

    for( int i = 0; i < n; i++ )
    {
        cin >> a >> b;
        for( int j = 0; j < b; j++ )
        {
            cin >> c;
            t[a].v.push_back(c);
            t[c].p = a;
        }
    }

    int cnt = 0;
    DFS( t, 1, cnt );

    for( int i = 1; i <= n; i++ )
    {
        if( t[i].min == 1000 )
            cout << i << " " << -1 << endl;
        else
            cout << i << " " << t[i].min << endl;
    }
    return 0;
}

C++: #include<iostream>
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int i=0;i<n;i++)
using P = pair<int,int>;

/* 大文字を小文字に変換 */
char tolower(char c) {return (c + 0x20);}
/* 小文字を大文字に変換 */
char toupr(char c) {return (c - 0x20);}

// if('A'<=s[i] && s[i]<='Z') s[i] += 'a'-'A';

/*
string s = "abcdefg"
s.substr(4) "efg"
s.substr(0,3) "abc"
s.substr(2,4) "cdef"

// イテレータ要素のインデックス
distance(A.begin(), itr);
*/

int main()
{
    int n; cin >> n;
    vector<int> to[n];
    rep(_,n){
        int u; cin >> u; --u;
        int k; cin >> k;
        rep(i,k){
            int v; cin >> v; --v;
            to[u].push_back(v);
        }
    }

    int dist[n];
    rep(i,n) dist[i] = -1;

    queue<int> q;
    q.push(0);
    dist[0] = 0;

    while(!q.empty()){
        int u = q.front(); q.pop();
        for(int v: to[u]){
            if(dist[v] == -1){
                dist[v] = dist[u]+1;
                q.push(v);
            }
        }
    }
    rep(i,n){
        printf("%d %d\n", i+1, dist[i]);
    }
}

C++: #include <stdio.h>
#include <string.h>
#include<iostream>
#include<queue>
using namespace std;

char s[13][1];
int D[102][102];
int A[100],f[100],w,h,n,sx,sy,gx,gy,e,g[100];
int   kensa(int ,int);
int main(){
	queue<int> P;
	int i,j,a,b,c,d;
	for(i=0;i<100;i++){
		for(j=0;j<100;j++){
			D[i][j]=-1;		
		}					
	}						
	for(i=0;i<100;i++){		
		A[i]=0;				
		f[i]=-1;
		g[i]=0;
	}							
	scanf("%d" ,&a);//     a=4
	for(i=1;i<=a;i++){
        scanf("%d",&b);		//
		scanf("%d",&b);			//b=2					//
		for(j=1;j<=b;j++){		//
		scanf("%d",&c);			//					//
		D[i][c]=1;
//
		}						//D[???][???]
	}				
	for(i=1;i<=a;i++){
		for(j=1;j<=a;j++){
		//	printf("%d %d %d\n",i,j,D[i][j]);
		}	
	}//
	P.push(1);
	//P???1
	f[0]=0;
	while(!P.empty()){			//
		d=P.front();
		//
		A[d]=1;
		//
		P.pop();				//
		for(i=1;i<=a;i++){
			//printf("%d %d %d\n",d,i,D[d][i]);//
			if(D[d][i]==-1){		//
			continue;			//
			}					//
			if(A[i]==1){		//
			continue;			//
			}					//
			P.push(i);			//
			f[i]=g[d]+1;
			g[i]=g[d]+1;
			A[i]=1;
			//printf("%d\n",P.back());
		}	
	}							//
	for(i=1;i<=a;i++){			//
	printf("%d %d\n",i, f[i]);	//
	}
	return 0;
}

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

const int nIMPOS = -1;
struct StDist
{
  int m_nDist;
  int m_nDone;

  StDist(int nDist) : m_nDist(nDist), m_nDone(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<StDist>& rvoDist)
{
  int nxSiz;
  cin >> nxSiz;

  rvvnAdjcy.resize(nxSiz + 1, vector<int>(nxSiz + 1, 0));
  for (int i = 0; i < nxSiz; ++i)
  {
    int nx, nySiz;
    cin >> nx >> nySiz;
    for (int j = 0; j < nySiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  StDist oDist(nIMPOS);
  rvoDist.resize(nxSiz + 1, oDist);
}

void fnBreadthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, 
                          queue<int>& rqnBFSrch, vector<StDist>& rvoDist)
{
  while (rqnBFSrch.size())
  {
    int nx = rqnBFSrch.front(); rqnBFSrch.pop();
    if (rvoDist[nx].m_nDist == nIMPOS)  continue;

    for (int ny = 1; ny < cnrvvnAdjcy[nx].size(); ++ny)
    {
      if (cnrvvnAdjcy[nx][ny] == 1  &&
          rvoDist[nx].m_nDone == 0)
      {
        int nDist = rvoDist[nx].m_nDist + 1;
        if (rvoDist[ny].m_nDist == nIMPOS)
          rvoDist[ny].m_nDist = nDist;
        else
          rvoDist[ny].m_nDist = min(rvoDist[ny].m_nDist, nDist);

        rqnBFSrch.push(ny);
      }
    }
    rvoDist[nx].m_nDone = 1;
  }
}

void fnResult(const vector<StDist>& cnrvoDist)
{
  for (int i = 1; i < cnrvoDist.size(); ++i)
    cout << i <<  " " << cnrvoDist[i].m_nDist << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  queue<int>  qnBFSrch;
  vector<StDist> voDist;

  fnInput(vvnAdjcy, voDist);

  voDist[1].m_nDist = 0;
  qnBFSrch.push(1);
  fnBreadthFirstSearch(vvnAdjcy, qnBFSrch, voDist);
  fnResult(voDist);

  return 0;
}

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

using namespace std;

static const int N = 100;
static const int INFTY = (1 << 21);
//static const int WHITE = 0;
//static const int GRAY = 1;
//static const int BLACK = 2;

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]) << '\n';
    }
}
int main() {
    int u, v, k;

    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;
}

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

const int Max = 105;
int G[Max][Max], color[Max], d[Max];
int n;

void bfs(int u)
{
    memset(color, -1, sizeof(color));
    memset(d, -1, sizeof(d));
    queue<int> Q;
    int v;
    Q.push(u);
    d[u] = 0;
    color[u] = 0;
    while(!Q.empty())
    {
        u = Q.front(); Q.pop();
        for(int i=0; i<n; i++)
        {
            if(G[u][i] && color[i]==-1)
            {
                color[i] = 0;
                Q.push(i);
                d[i] = d[u]+1;
            }
        }
    }
    for(int i=0; i<n; i++)
    {
        cout << i+1 << " " << d[i] << endl;
    }
}

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