Go: package main

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

type AdjacentList struct {
	matrix [][]int
}

func NewEmptyAdjacentList(dim int) *AdjacentList {
	matrix := make([][]int, dim)
	for i := 0; i < dim; i++ {
		matrix[i] = make([]int, dim)
	}
	return &AdjacentList{matrix: matrix}
}

func (al *AdjacentList) set(node int, adjacent int) {
	al.matrix[node-1][adjacent-1] = 1
}

func (al *AdjacentList) findAdjacentsFor(node int) []int {
	adjacents := []int{}
	for i, v := range al.matrix[node-1] {
		if v == 1 {
			adjacents = append(adjacents, i+1)
		}
	}
	return adjacents
}

type DistanceList struct {
	list []int
}

func NewDistanceList(dim int) *DistanceList {
	list := make([]int, dim)
	for i := 0; i < dim; i++ {
		list[i] = -1
	}
	return &DistanceList{list: list}
}

func (dl *DistanceList) set(node int, distance int) {
	dl.list[node-1] = distance
}

func (dl *DistanceList) get(node int) int {
	return dl.list[node-1]
}

func (dl *DistanceList) isVisited(node int) bool {
	return dl.list[node-1] >= 0
}

type Position struct {
	node     int
	distance int
}

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

	dim, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	al := NewEmptyAdjacentList(dim)

	for i := 1; i <= dim; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}

		adjacentNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		for j := 0; j < adjacentNum; j++ {
			adjacent, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			al.set(node, adjacent)
		}
	}

	dl := NewDistanceList(dim)

	bfs(al, dl)

	for i := 1; i <= dim; i++ {
		fmt.Printf("%d %d\n", i, dl.get(i))
	}
}

func bfs(al *AdjacentList, dl *DistanceList) {
	stack := []Position{Position{node: 1, distance: 0}}
	for len(stack) > 0 {
		currentPosition := stack[0]
		stack = stack[1:]
		if !dl.isVisited(currentPosition.node) {
			dl.set(currentPosition.node, currentPosition.distance)
		}
		for _, v := range al.findAdjacentsFor(currentPosition.node) {
			stack = append(stack, Position{node: v, distance: currentPosition.distance + 1})
		}
	}
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

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

int n;
int graph[100][100];
int INF = -100000007;
// 未探索はINF
int d[100];

int main() {

  cin >> n;

  // 配列を初期化
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < n; j++) {
      graph[i][j] = 0;
    }
    d[i] = INF;
  }

  // 入力を受け取る
  for(int i = 0; i < n; i++) {
    int u, k;
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int v;
      cin >> v;
      graph[u - 1][v - 1] = 1;
    }
  }

  // 頂点1を設定
  queue<int> q;
  q.push(0);
  d[0] = 0;

  // 探索
  while (!q.empty()) {
    int u = q.front(); q.pop();
    for (int i = 0; i < n; i++) {
      if (graph[u][i] == 0) {
        continue;
      }
      if (d[i] != INF) {
        continue;
      }
      d[i] = d[u] + 1;
      q.push(i);
    }
  }

  // 探索結果を出力
  for (int i = 0; i < n; i++) {
    if (d[i] == INF) {
      cout << i + 1 << " -1" << endl;
    } else{
      cout << i + 1 << " " << d[i] << endl;
    }
  }

  return 0;

}