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++: //============================================================================
// Name        : Graph.cpp
// Author      : Ken
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

struct Node{
	int id;
	vector<int> adjNodes;
	bool isFound;
	int discover_time;
	int finish_time;
	int distance;
};

class Graph{
public:
	vector<Node> nodeList;
	map<int, vector<Node*> > distanceMap;
	Graph():nodeList(), distanceMap(){}

	void insert(Node& i){
		nodeList.push_back(i);
	}

	void SearchDepthFirst(int source_id, int& timer){
		Node& source_node = nodeList.at(source_id);
		source_node.isFound = true;
		source_node.discover_time = timer;
		for(int i=0; i<source_node.adjNodes.size(); i++){
			if(nodeList.at(source_node.adjNodes.at(i)).isFound == false){
				timer ++;
				nodeList.at(source_node.adjNodes.at(i)).isFound = true;
				nodeList.at(source_node.adjNodes.at(i)).discover_time = timer;
				SearchDepthFirst(source_node.adjNodes.at(i), timer);
				nodeList.at(source_node.adjNodes.at(i)).finish_time = timer;
			}
		}
		timer++;

		source_node.finish_time = timer;
	}

	void SearchDepthFirstAll(int& timer){
		for(int i=0; i<nodeList.size(); i++){
			if(nodeList.at(i).isFound == false){
				SearchDepthFirst(i, timer);
				timer++;
			}
		}
	}

	void writeSearchResult(){
		for(int i=0; i<nodeList.size(); i++){
			cout << nodeList.at(i).id+1 << " " << nodeList.at(i).discover_time << " " << nodeList.at(i).finish_time << "\n";
		}
	}


	void addDistance(){
		vector<Node*> vec;
		vec.push_back(&nodeList.at(0));
		distanceMap[0] =vec;
		int cur_distance=0;

		while(cur_distance < nodeList.size()){
			vector<Node*>& vec_p_node = distanceMap[cur_distance];
			vector<Node*> empty_vec;
			distanceMap[cur_distance+1] = empty_vec;
			for(int i=0; i<vec_p_node.size(); i++){
				vector<int>& adjNodes = vec_p_node.at(i)->adjNodes;
				for(int j=0; j<adjNodes.size(); j++){
					if(nodeList.at(adjNodes.at(j)).distance == -1){
					    nodeList.at(adjNodes.at(j)).distance = cur_distance+1;
					    distanceMap[cur_distance+1].push_back(&nodeList.at(adjNodes.at(j)));
					}
				}
			}
			if(distanceMap[cur_distance+1].size() == 0){
				break;
			}

			cur_distance++;
		}
	}

	void writeDistance(){
		for(int i=0; i<nodeList.size(); i++){
			cout << i+1 << " " << nodeList.at(i).distance << "\n";
		}
	}

	void write(){
		for(int i=0; i<nodeList.size(); i++){
			Node& node = nodeList.at(i);
			cout << node.id << " " << node.adjNodes.size() << " ";

			for(int j=0; j<node.adjNodes.size(); j++){
				cout << node.adjNodes.at(j) << " ";
			}
			cout << "\n";
		}

	}

	void writeMap(){
		map<int, vector<Node*> >::iterator p;
		for(p=distanceMap.begin(); p!=distanceMap.end(); ++p){
			cout << "distance: " << p->first << ", id: ";
			vector<Node*>::iterator p2;
			for(p2=p->second.begin(); p2!=p->second.end(); ++p2){
				cout << (*p2)->id << " ";
			}
			cout << "\n";
		}
	}
};

void writeMatrix(vector<vector<int> > matrix){
	for(int i=0; i<matrix.size(); i++){
		for(int j=0; j<matrix.at(i).size()-1; j++){
			cout << matrix.at(i).at(j) << " ";
		}
		cout << matrix.at(i).at(matrix.at(i).size()-1);
		cout << "\n";
	}
}

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

	for(int i=0; i<n; i++){
		int id, k;
		cin >> id >> k;
		vector<int> adjNodes;
		for(int j=0; j<k; j++){
			int input;
			cin >> input;
			adjNodes.push_back(input-1);
		}
		sort(adjNodes.begin(), adjNodes.end());
		Node node = {id-1, adjNodes, false, -1, -1, -1};
		g.insert(node);
	}

	//g.write();
	//int timer = 1;
	//g.SearchDepthFirstAll(timer);
	//g.writeSearchResult();

	g.nodeList.at(0).distance = 0;
	g.addDistance();
	g.writeDistance();

	return 0;
}

C++: //http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_C&lang=jp

#include <iostream>
#include <queue>
using namespace std;
static const int INFTY = (1<<21);

int N;
int E[100][100];
int d[100];

void bfs(int s){
  queue<int> q;
  q.push(s);
  for (int j = 0; j < N; j++)d[j]=INFTY;
  d[s] = 0;
  int u;
  while(!q.empty()){
    u = q.front();
    q.pop();
    for(int v = 0; v < N; v++){
      if(E[u][v] == 0) continue;
      if(d[v] != INFTY) continue;
      d[v] = d[u] + 1;
      q.push(v);
    }
  }
  for(int k = 0; k < N; k++){
    if(d[k] == INFTY){
      cout << k+1 << " " << -1 << endl;
    }else{
      cout << k+1 << " " << d[k] << endl;
    }
  }
}



int main(){
  //Eへのグラフ情報の代入
  cin >> N;
  for (int i = 0; i < N; i++){
    for (int j = 0; j < N; j++){
      E[i][j] = 0;
    }
  }
  for ( int i = 0; i < N; i++){
    int dummy;
    cin >> dummy;
    int n;
    cin >> n;
    for (int c = 0; c < n; c++){
      int dest;
      cin >> dest;
      E[dummy-1][dest-1] = 1;
    }
  }

  bfs(0);

  return 0;


}

C++: #include <iostream>
#include <queue>
const int MAX_N = 100;
const int INF = 999999999;
using namespace std;

int n;
int color[MAX_N];
bool adj[MAX_N][MAX_N];
int d[MAX_N];

void bfs(int s) {
    queue<int> que; que.push(s);
    for (int i = 0; i < n; i++) d[i] = INF;
    d[s] = 0;

    int u;
    while (!que.empty()) {
        u = que.front(); que.pop();
        for (int v = 0; v < n; v++) {
            if (adj[u][v] && d[v] == INF) {
                d[v] = d[u] + 1;
                que.push(v);
            }
        }
    }
}
int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            adj[i][j] = false;
        }
    }

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

    bfs(0);

    for (int i = 0; i < n; i++) {
        if (d[i] != INF) {
            cout << i+1 << " " << d[i] << endl;
        } else {
            cout << i+1 << " " << -1 << endl;
        }
    }

    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <stack>
#include <climits>
#include <map>
#include <set>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

const ll mod = 1000000007;
const int inf = 1e9;
const long long INF = 1LL << 60;

vector<int> G[105];
int d[105];

int main()
{
    int n; cin >> 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[u].push_back(x);
        }
    }
    for(int i = 0; i < 105; i++){
        d[i] = -1;
    }
    queue<int> q;
    d[0] = 0;
    q.push(0);
    while(!q.empty()){
        int u = q.front(); q.pop();
        for(int i = 0; i < G[u].size(); i++){
            int nv = G[u][i];
            if(d[nv] == -1){
                d[nv] = d[u] + 1;
                q.push(nv);
            }
        }
    }
    for(int i = 0; i < n; i++){
        cout << i+1 << ' ' << d[i] << endl;
    }
}