Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include<iostream>
#include<vector>
using namespace std;
const int MAX = 100;
const int INF = 10000000;
int n, G[MAX][MAX];
int dis[MAX];
bool Flag[MAX] = { false };
void init()
{
	for (int i = 0; i < n; i++)
		dis[i] = G[0][i];
	Flag[0] = true;
}
void dijkstra()
{
	for (int k = 1; k <= n - 1; k++)
	{
		int min = INF;
		int u;
		for (int j = 0; j < n; j++)
			if (dis[j] > 0 && dis[j] < INF && !Flag[j] && dis[j] < min)
			{
				min = dis[j];
				u = j;
			}
		Flag[u] = true;
		for (int v = 0; v < n; v++)
			if (!Flag[v] && dis[u]+G[u][v] < dis[v])
				dis[v] = dis[u] + G[u][v];
	}
}
int main()
{
	cin >> n;
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			if (i != j)
				G[i][j] = INF;
			else
				G[i][j] = 0;
	for (int i = 0; i < n; i++)
	{
		int u, d;
		cin >> u >> d;
		for (int j = 0; j < d; j++)
		{
			int v, w;
			cin >> v >> w;
			G[u][v] = w;
		}
	}
	init();
	dijkstra();
	for (int i = 0; i < n; i++)
		cout << i << " " << dis[i] << endl;
}

C++: #include<stdio.h>
main()
{
  int i,j,n,g,count=0;
  int V,A,A1,V1;
  int G[101][101],c[101],INF[101],p[101],mincost;

  for(i = 0; i < 101; i++){
    for(j = 0; j < 101; j++)
      G[i][j] = -1;
  }

  scanf("%d",&n);

  for(i = 0; i < n; i++){
    scanf("%d%d",&V,&A);
    for(j = 0; j < A; j++){
      scanf("%d%d",&V1,&A1);
      G[A][A1] = A1;
    }
  }

  for(i = 0; i < n; i++){
    c[i] = 0;
    p[i] = -1;
    INF[i] = 10000001;
  }

  INF[0] = 0;

  while(1){
    mincost = 10000001;
    for(i = 0; i < n; i++){
      if(c[i] != 2 && INF[i] < mincost){
        mincost = INF[i];
        g = i;
      }
    }
    if(mincost == 10000001)break;

    c[g] = 2;


    for(i = 0; i < n; i++){
      if(G[g][i] != -1 && c[i] != 2 && (G[g][i]+INF[g]) < INF[i]){
        p[i] = g;
        INF[i] = G[g][i] + INF[g];
        c[i] = 1;
      }
    }
  }
INF[0] = 0;

  while(1){
    mincost = 10000001;
    for(i = 0; i < n; i++){
      if(c[i] != 2 && INF[i] < mincost){
        mincost = INF[i];
        g = i;
      }
    }
    if(mincost == 10000001)break;

    c[g] = 2;


    for(i = 0; i < n; i++){
      if(G[g][i] != -1 && c[i] != 2 && (G[g][i]+INF[g]) < INF[i]){
        p[i] = g;
        INF[i] = G[g][i] + INF[g];
        c[i] = 1;
      }
    }
  }
  for(i = 0; i < n; i++)printf("%d %d\n",i,INF[i]);
  return 0;
}

C++: #include<iostream>
using namespace std;
static const int MAX = 100;
static const int INFTY = (1<<21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[MAX][MAX];

void dijkstra() {
  int minv;
  int d[MAX], color[MAX];

  for ( int i = 0; i < n; i++ ) {
    d[i] = INFTY;
    color[i] = WHITE;
  }

  d[0] = 0;
  color[0] = GRAY;
  while ( 1 ) {
    minv = INFTY;
    int u = -1;
    for ( int i = 0; i < n; i++ )
      if ( minv > d[i] && color[i] != BLACK ) {
        u = i;
        minv = d[i];
      }
    if ( u == -1 ) break;
    color[u] == BLACK;
    for ( int v = 0; v < n; v++ )
      if ( color[v] != BLACK && M[u][v] != INFTY )
        if ( d[v] > d[u] + M[u][v] ) {
          d[v] = d[u] + M[u][v];
          color[v] = GRAY;
        }
  }

  for ( int i = 0; i < n; i++ )
    cout << i << " " << ( d[i] == INFTY ? -1 : d[i] ) << endl;
}

int main() {
  cin >> n;
  for ( int i = 0; i < n; i++ )
    for ( int j = 0; j < n; j++ )
      M[i][j] = INFTY;

  int k, c, u, v;
  for ( int i = 0; i < n; i++ ) {
    cin >> u >> k;
    for ( int j = 0; j < k; j++ ) {
      cin >> v >> c;
      M[u][v] = c;
    }
  }

  dijkstra();

  return 0;
}

C++: //http://www.deqnotes.net/acmicpc/dijkstra/を参照
//単一始点最短経路
//プライオリティーキューでの実装がよくわからない
#include<iostream>
#include<algorithm>
#include<utility>
#include<vector>
//#include<queue>
using namespace std;

struct Node{
  //ノードの情報
  int num;//ノードの番号
  vector<pair<int,int>> edge;//各エッジの接続先のノード番号とコスト

  //ダイクストラ法用のデータ
  bool confirmed;//確定ノードかどうか
  int mincost;//そのノードへの最小コスト(確定かどうかはconfirmedで決まる)
};
/*
 下の不等号のみで十分(min_costは<のみ使っている)
bool operator>(const Node node1,const Node node2){
  return node1.mincost > node2.mincost;
}
*/
bool operator<(const Node node1,const Node node2){
  return node1.mincost < node2.mincost;
}
/*
bool compare_pair(const pair<int,int> x,const pair<int,int> y){
  return x.second < y.second;
}
*/

pair<vector<pair<int,int>>::iterator,vector<pair<int,int>>::iterator> dijkstra1(vector<Node> Nodex){
  //優先度の低いものを取りだす(popで)
  //取り出したものが接続するノードのmincostを取り出す
  vector<pair<int,int>> c;
  while(Nodex.size()!=0){
    vector<Node>::iterator x=min_element(Nodex.begin(),Nodex.end());
    x->confirmed=true;//これいらない気もする
    c.push_back(make_pair(x->num,x->mincost));
    for(auto i=x->edge.begin();i<x->edge.end();i++){
      vector<Node>::iterator k=Nodex.end();
      for(vector<Node>::iterator j=Nodex.begin();j<Nodex.end();j++){
        if(j->num==i->first){
          k=j;
          break;
        }
      }
      //この下、ループの中でできる、kを定義する必要もない
      if(k!=Nodex.end()){
        if(k->mincost==1000000000){
          k->mincost=x->mincost+ i->second;
        }else{
          //1000000000は十分に大きいのでこの下のみを書けば十分
          k->mincost=min(k->mincost,x->mincost+ i->second);
        }
      }
    }
    Nodex.erase(x);
  }
  sort(c.begin(),c.end());
  return make_pair(c.begin(),c.end());
}

int main(){
  int n;
  vector<Node> Nodes;
  int u,k;
  int v,c;
  cin >> n;
  for(int i=0;i<n;i++){
    Node subNode;
    cin >> u >> k;
    subNode.num=u;
    subNode.confirmed=false;
    if(subNode.num==0){
      //始まりのノードを確定済みにする
      subNode.mincost=0;
    }else{
      subNode.mincost=1000000000;
    }//int型の最大値に近い
    for(int j=0;j<k;j++){
      cin >> v >> c;
      subNode.edge.push_back(make_pair(v,c));
    }
    Nodes.push_back(subNode);
  }
  pair<vector<pair<int,int>>::iterator,vector<pair<int,int>>::iterator> d=dijkstra1(Nodes);
  for(vector<pair<int,int>>::iterator i=d.first;i<d.second;i++){
    cout << (*i).first << " " << (*i).second << endl;
    //cout <, i->first << " " << i->second << endl;でも同じ
  }
}