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++: #define N 1000
#define M -1
#include <iostream>
#include <vector>
#include <queue>
using namespace std;

int m[N][N] = {};
int d[N] = {};
int n;

int main() {
	cin >> n;
	for (int i = 1; i <= n; i++)d[i] = M;
	int j;
	for (int i = 0; i < n; i++) {
		int k;
		int u;
		int v;
		cin >> u;
		cin >> k;
		for (j = 0; j < k; j++) {
			cin >> v;
			m[u][v] = 1;
		}
	}
	queue<int> q;
	q.push(1);
	d[1] = 0;
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		if (d[u] != M) {
			for (int i = 1; i <= n; i++) {
				if (m[u][i]) {
					if (d[i] == M) {
						d[i] = d[u] + 1;
						q.push(i);
						//cout << "a" << endl;
					}
				}
			}
		}
	}
	for (int i = 1; i <= n; i++) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

C++: #define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

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



using namespace std;




int main() {
	
	int n;
	cin>>n;
	vector<vector<int>>t(n,vector<int>(0));
	for(int i=0;i<n;i++){
		int a,b;
		cin>>a>>b;
		for(int j=0;j<b;j++){
			int x;
			cin>>x;x--;t[i].push_back(x);
		}
	}
	queue<int>r;
	r.push(0);
	int g[105]={1000000};
	for(int i=0;i<n;i++){
		g[i]=10000000;
	}
	g[0]=0;
	set<int>p;
	p.insert(0);
	while(r.size()||p.size()<n){
		if(!r.size()){
			for(int i=0;i<n;i++){
				if(g[i]==10000000){
					g[i]=-1;
					p.insert(i);
					//r.push(i);
				}
			}
		}
		else{
		int v=r.front();
		for(int i=0;i<t[v].size();i++){
			r.push(t[v][i]);
			p.insert(t[v][i]);
			g[t[v][i]]=min(g[t[v][i]],g[v]+1);
			
		}
		r.pop();
		
		}
	}
	for(int i=0;i<n;i++)
		cout<<i+1<<" "<<g[i]<<endl;

	
	return 0;
}

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

using namespace std;

const int WHITE = 0, GREY = 1, BLACK = 2;
const int INF = 1000000;

struct BFS {
    int n;
    vector<vector<int>> g;
    vector<int> parent;
    vector<int> distance;
    vector<int> color;
    
    BFS (int n) : n(n) {
        g.assign(n, vector<int>(0));
        parent.assign(n, -2);
        distance.assign(n, INF);
        color.assign(n, WHITE);
    }
    
    void addEdge (int u, int v) {
        g[u].push_back(v);
    }
    
    void bfs (int s) {
        queue<int> q;
        q.push(s);
        parent[s] = -1;
        distance[s] = 0;
        color[s] = GREY;
        while (!q.empty()) { //u = current, v = neighbors
            int u = q.front();
            q.pop();
            for (int v : g[u]) {
                if (color[v] == WHITE) {
                    q.push(v);
                    parent[v] = u;
                    distance[v] = distance[u] + 1;
                    color[v] = GREY;
                }
            }
            color[u] = BLACK;
        }
    }
    
    void printResults () {
        for (int i = 0; i < n; i++) {
            int dist = distance[i];
            if (dist == INF) {
                dist = -1;
            }
            cout << i + 1 << " " << dist << endl;
        }
    }
};

int main() {
    
    int n;
    cin >> n;
    BFS bfs(n);
    
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            bfs.addEdge(u - 1, v - 1);
        }
    }
    
    bfs.bfs(0);
    bfs.printResults();
    
    return 0;
}