Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, 0, n)
	for i := 0; i < n; i++ {
		ds = append(ds, -1)
	}

	q := make([]int, 0, n)
	q = append(q, 0)
	ds[0] = 0

	for len(q) > 0 {
		i := pop(&q)
		for _, v := range vecs[i] {
			if ds[v] == -1 {
				ds[v] = ds[i]+1
				q = append(q, v)
			}
		}
	}

	for i, d := range ds {
		fmt.Fprintln(w, i+1, d)
	}

	w.Flush()
}

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

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, a, b) for (int i = a; i < b; i++)
#define all(v) v.begin(), v.end()
const int MOD = 1e9 + 7;
const int INF = 2e9;
//'A' = 65, 'Z' = 90, 'a' = 97, 'z' = 122

int main() {
    int n;
    cin >> n;
    vector<vector<int>> g(n);
    rep(i, 0, n) {
        int u, k;
        cin >> u >> k;
        u--;
        rep(j, 0, k) {
            int v;
            cin >> v;
            v--;
            g[u].push_back(v);
        }
    }

    int dist[n];
    rep(i, 0, n) dist[i] = -1;
    dist[0] = 0;
    queue<int> q;
    q.push(0);

    while (!q.empty()) {
        int x = q.front();
        q.pop();
        rep(i, 0, (int)g[x].size()) {
            int nx = g[x][i];
            if (dist[nx] != -1) continue;
            dist[nx] = dist[x] + 1;
            q.push(nx);
        }
    }

    rep(i, 0, n) {
        cout << i + 1 << " " << dist[i] << endl;
    }

    return 0;
}

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

int main() {
	int n, u, k, v;
	cin >> n;
	vector<vector<int>> a(n);
	for (int i = 0; i < n; ++i) {
		cin >> u >> k;
		for (int j = 0; j < k; ++j) {
			cin >> v;
			a[u - 1].push_back(v - 1);
		}
	}
	queue<int> b;
	b.push(0);
	vector<int> ans(n, -1);
	ans[0] = 0;
	while (!b.empty()) {
		for (int& i : a[b.front()]) {
			if (-1 == ans[i]) {
				ans[i] = 1 + ans[b.front()];
				b.push(i);
			}
		}
		b.pop();
	}
	for (int i = 0; i < n; ++i) cout << 1 + i << ' ' << ans[i] << endl;
}

C++: #include<bits/stdc++.h>
#define ll long long
#define rep(i, n) for(int i=0; i<n; i++)
#define REP(i, n) for(int i=0; i<=n; i++)
#define repr(i, n) for(int i=n; i>0; i--)
#define REPR(i, n) for(int i=n; i>=0; i--)
const ll INF = 1LL<<60;
const int INT_INF = 1e9;
const ll MOD = 1e9+7;
template<class T> void puts(T x) { std::cout << x << std::endl; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
using namespace std;

enum State {
    unseen, // 未訪問
    seen,   // 発見済み
    end     // 探索終了
};

vector<vector<int>> adj; // 隣接行列
int t = 0;  // 大域時刻
int d[110]; // 各頂点の頂点1からの最短距離
State s[110];


int main() {
    int n; cin >> n;
    adj.resize(n);
    rep(i, n) {
        int u, k; cin >> u >> k;
        --u;
        rep(j, k) {
            int v; cin >> v;
            --v;
            adj[i].emplace_back(v);
        }
    }

    // 初期化
    rep(i, n) {
        d[i] = INT_INF;
        s[i] = State::unseen;
    }
    d[0] = 0;
    queue<int> q;
    q.push(0);

    // BFS
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        for (auto &v: adj[u]) {
            if (d[v] == INT_INF) {
                q.push(v);
                d[v] = d[u] + 1;
            }
        }
    }

    // 出力
    rep(i, n) {
        int dist = (d[i] != INT_INF) ? d[i] : -1;
        cout << i+1 << ' ' << dist << endl;
    }
}

C++: #include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>
 
#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
 
using namespace std;
 
typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;
 
const int INF=1<<29;
const double EPS=1e-9;
 
const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};

std::vector<vector<int> > G;
std::vector<int> flag;
std::vector<int> in;
int N;


int main(int argc, char const *argv[]) {
	
	cin >> N;

	for (int i = 0; i < N; ++i) {
		G.push_back(vector<int>());
		flag.push_back(0);
		in.push_back(0);
		for (int j = 0; j < N; ++j) {
			G[i].push_back(0);
		}
	}

	for (int i = 0; i < N; ++i) {
		int u, k;
		cin >> u >> k;
		u--;
		for (int j = 0; j < k; ++j) {
			int v;
			cin >> v;
			v--;
			G[u][v] = 1;
		}
	}
	using P = pair<int,int>;
	queue<P> q;
	q.push(mp(0, 0));
	while(!q.empty()) {
		P u = q.front(); q.pop();
		int dist = u.second;
		in[u.first] = dist;
		for (int i = 0; i < N; ++i) {
			if (flag[i] == 0 && G[u.first][i] == 1) {
				q.push(mp(i, dist + 1));
				flag[i] = 1;
			}
		}
	}

	for (int i = 0; i < N; ++i) {
		cout << i + 1 << " " << in[i] << endl;
	}

	return 0;
}

C++: // #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define Graph vector< vector<int> >
typedef long long ll;
typedef pair<int, int> P;
const int INF = 1000000007;

int main(){
    int N;
    cin >> N;
    Graph G(N);
    rep(i, N){
        int u, k;
        cin >> u >> k;
        u--;
        rep(j, k){
            int v;
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }

    vector<int> dist(N, -1);
    dist[0] = 0;

    queue<int> que;
    que.push(0);

    while(!que.empty()){
        int v = que.front();
        que.pop();
        for(int i = 0; i < G[v].size(); i++){
            int v2 = G[v][i];
            if(dist[v2] != -1) continue;
            dist[v2] = dist[v] + 1;
            que.push(v2);
        }
    }

    rep(i, N){
        cout << i + 1 << ' ' << dist[i] << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;

using edges = vector<int>;
using Graph = vector<edges>;

int main() {
    int n;
    cin >> n;
    Graph g(n);
    for (int i = 0; i < n; ++i) {
        int u, k;
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; ++j) {
            int v;
            cin >> v;
            v--;
            g[u].push_back(v);
        }
    }
    queue<int> que;
    que.emplace(0);
    vector<int> dis(n, -1);
    dis[0] = 0;
    while (!que.empty()) {
        int v = que.front(); que.pop();
        for (int nv : g[v]) if (dis[nv] < 0) {
            dis[nv] = dis[v] + 1;
            que.emplace(nv);
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << i + 1 << " " << dis[i] << endl;
    }
}