Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

func stringifyArray(arr []int) string {
	return strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]")
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, &g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

func fillDistancesByBreadthFirstSearch(g *DirectedGraph, startNode *DirectedGraphNode) {
	startNode.visited = true
	startNode.d = 0

	queue := Queue{}
	queue.enqueue(startNode)
	for !queue.isEmpty() {
		u := queue.dequeue().node
		for _, adjacent := range u.adjacents {
			if !adjacent.visited {
				adjacent.visited = true
				adjacent.d = u.d + 1
				adjacent.parent = u
				queue.enqueue(adjacent)
			}
		}
		u.visited = true
	}
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	// fmt.Println(g)
	fillDistancesByBreadthFirstSearch(g, &g.nodes[1])
	// fmt.Println(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		distance := node.d
		if distance == infty {
			distance = -1
		}
		fmt.Println(node.key, distance)
	}
}

C++: #if 0
	??????????????????????????????
#endif
#include <iostream>
#include <queue>

using namespace std;

int main(){
	int n, u, k, v;
	int D[100];
	bool adj[100][100] = {};
	int pushed[100] = {};
	cin >> n;
	for (int i = 1; i <= n; i++){
		cin >> u >> k;
		for (int j = 1; j <= k; j++){
			cin >> v;
			adj[u][v] = true;
		}
	}
	for (int i = 1; i <= n; i++){
		D[i] = -1;
	}
	queue<int> Q;
	Q.push(1);
	D[1] = 0;
	pushed[1] = 1;
	while(!Q.empty()){
		int m = Q.front();
		Q.pop();
		for (int i = 1; i <= n; i++){
			if (adj[m][i] == true && pushed[i] == 0){
				D[i] = D[m]+1;
				Q.push(i);
				pushed[i] = 1;
			}
		}
	}
	
	for (int i = 1; i < n+1; i++){
		cout << i << ' ' << D[i] << endl;
	}
}

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;
    }
}