Go: package main

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

type Pair struct {
	v int
	d int
}

type Queue []Pair

func (q *Queue) push(v Pair) {
	*q = append(*q, v)
}

func (q *Queue) pop() Pair {
	v := (*q)[0]
	*q = (*q)[1:]
	return v
}

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

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	paths := make([]int, nVerts+1)

	queue := Queue(make([]Pair, 0))
	queue.push(Pair{1, 1})
	paths[1] = 1

	for len(queue) > 0 {
		p := queue.pop()
		d := p.d + 1
		for _, v := range graph[p.v] {
			if paths[v] == 0 {
				paths[v] = d
				queue.push(Pair{v, d})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d\n", i, paths[i]-1)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

C++: #include <iostream>
#include <fstream>
#include <stdio.h>
#include <math.h>
#include <algorithm>
#include <queue>

using namespace std;

int n;
int arr[100][100];
int time_saver[100][2];
int now_time;
queue< pair < int, int > > q;

void search(int fi, int fnow_time){
    time_saver[fi][0] = fnow_time;
    for(int i=0; i<100; i++){
        if(arr[fi][i] && !time_saver[arr[fi][i]-1][0]){
            int a = fnow_time+1;
            q.push(make_pair(arr[fi][i]-1, a));
        }
    }
}

int main(int argc, const char * argv[]) {
    
    /////////
    //write//
    /////////
    
    cin >> n;
    now_time = 0;
    for(int i=0; i<100; i++){
        for(int j=0; j<100; j++){
            arr[i][j] = 0;
        }
        for(int j=0; j<2; j++){
            time_saver[i][j] = 0;
        }
    }
    
    for(int i=0; i<n; i++){
        int node, degree; cin >> node >> degree;
        for(int j=0; j<degree; j++){
            int tmp; cin >> tmp;
            arr[node-1][tmp-1] = tmp;
        }
    }
    
    for(int i=0; i<1; i++){
        if(time_saver[i][0])continue;
        search(i, now_time);
        while(!q.empty()){
            int tmp = q.front().first;
            int tmp2 = q.front().second;
            now_time = max(now_time, q.front().second+1);
            q.pop();
            if(time_saver[tmp][0] || tmp == 0)continue;
            search(tmp, tmp2);
        }
    }
    for(int i=1; i<n; i++){
        if(!time_saver[i][0])time_saver[i][0] = -1;
    }
    
    for(int i=0; i<n; i++){
        for(int j=0; j<1; j++){
            if(j)cout << " ";
            else cout << i+1 << " ";
            cout << time_saver[i][j];
        }
        cout << endl;
    }
    
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <cstdio>
using namespace std;
 
int n;
vector <int> G[101];
queue <int> Q;
int  d[100];
int  dis[101];
 
 
int visit(int x){
  int t,i;
   
  Q.push(x);
  dis[x] = 0;
  d[x] = 1;
 
  while(Q.empty() == false) {
     
    // cout << "start Q" <<endl;
 
    t = Q.front();
    Q.pop();
 
    for(i=0; i<G[t].size();i++) {
      if(d[G[t][i]] == 0 ) {
    d[G[t][i]] = 1;
    dis[G[t][i]] = dis[t] + 1;
 
    Q.push(G[t][i]);
      }
 
    }
  }
}
     
int main() {
   
  int i,j,k,l,u,a,t;
   
   
  scanf("%d",&n);
 
   
   
  for(i=0;i<n;i++){
    d[i] = 0;
    dis[i] = -1;
    scanf("%d %d ",&k,&u);
     
    for(j=0;j<u;j++) {
      scanf("%d",&a);
      G[k-1].push_back(a-1);
      // printf("G[%d][%d] = 1\n",i,k-1);
    }
  }
   
   
  visit(0);
 
   
 
  for(i=0;i<n;i++) cout << i+1<<" " << dis[i] <<endl;
 
 
 
  return 0;
 
     
     
}

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

char s[13][1];
int D[102][102];
int A[103],f[103],w,h,n,sx,sy,gx,gy,e,g[103];
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[1]=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 <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = s; i < (int)(n); i++)
#define rep3(i, s, n) for (int i = s; i > (int)(n); i--)
#define all(obj) obj.begin(), obj.end()
#define db(x) cerr << #x << ":" << x << " "
#define dbl(x) cerr << #x << ":" << x << "\n"
#define dbv(vec) cerr << #vec << ":"; for (auto e : vec) cerr << e << " "; cout << "\n"
#define dbvv(vv) cerr << #vv << ":\n"; for (auto vec : vv) { for (auto e : vec) cerr << e << " "; cerr << "\n"; }
#define dbm(map) cerr << #map << ":"; for (auto p : map) cerr << "(" << p.first << ", " << p.second << "), "; cerr << "\n";
#define YN(f) cout << (f ? "YES" : "NO") << "\n"
#define Yn(f) cout << (f ? "Yes" : "No") << "\n"
#define yn(f) cout << (f ? "yes" : "no") << "\n"
using ll = long long;
using vi = vector<int>; using vl = vector<ll>; using vs = vector<string>; using vb = vector<bool>;
using vvi = vector<vi>; using vvl = vector<vl>; using vvb = vector<vb>;
using pii = pair<int, int>; using pll = pair<ll, ll>;
using vpii = vector<pii>; using vpll = vector<pll>;
using ti3 = tuple<int, int, int>; using tl3 = tuple<ll, ll, ll>;
using mii = map<int, int>; using mil = map<int, ll>; using mli = map<ll, int>; using mll = map<ll, ll>;

int main() {
	int n; cin >> n;
	vvi g(n + 1); vi d(n + 1, -1); // 1-ind
	rep2(i, 1, n + 1) {
		int _, k; cin >> _ >> k;
		rep(j, k) {
			int v; cin >> v;
			g[i].push_back(v);
		}
	}
	// dbvv(g);
	queue<int> q;
	q.push(1); d[1] = 0;
	while (!q.empty()) {
		int u = q.front(); q.pop();
		for (int v : g[u]) {
			if (d[v] != -1) continue;
			d[v] = d[u] + 1;
			q.push(v);
		}
	}
	rep2(i, 1, n + 1) printf("%d %d\n", i, d[i]);
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <cmath>
#include <deque>
#include <iterator>
#include <map>
#include <queue>
#include <string>
#include <tuple>
#include <utility>
using namespace std;

using ll=long long;
template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;
using vll = V<ll>;
using vvll = V<vll>;
#define rep(i, k, n) for (ll i=k; i<(ll)n; ++i)
#define REP(i, n) rep(i, 0, n)
template<class T> inline bool chmax(T& a, T b) {if (a<b) {a=b; return true;} return false;}
template<class T> inline bool chmin(T& a, T b) {if (a>b) {a=b; return true;} return false;}

int main() {
  ll n; cin >> n;
  vvll edges(n, vll());
  REP(i, n) {
    ll u, k; cin >> u >> k;
    REP(j, k) {
      ll to; cin >> to;
      edges.at(u-1).push_back(to-1);
    }
  }
  vll d(n, -1);
  V<bool> visited(n, false);
  queue<ll> q; q.push(0);
  ll tmpd = 0;
  while (!q.empty()) {
    queue<ll> tmpq;
    while (!q.empty()) {
      ll to = q.front(); q.pop();
      if (visited.at(to)) continue;
      visited.at(to) = true; d.at(to) = tmpd;
      REP(i, edges.at(to).size()) {
        if (visited.at(edges.at(to).at(i))) continue;
        tmpq.push(edges.at(to).at(i));
      }
    }
    q = tmpq; tmpd++;
  }
  REP(i, n) cout << i+1 << ' ' << d.at(i) << endl;
  return 0;
}