Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

C++: //http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_12_B&lang=jp
#include<bits/stdc++.h>
#pragma warning(disable:4996)
using namespace std;
using ll = long long;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
const int INF = numeric_limits<int>::max();
struct edge {
	int from, to, cost;
};
vector<int> dijkstra(int s, vector<vector<edge>>&graph) {//頂点sからほかのすべての頂点の最短距離を入れたvectorを返す
	//以下pair<int,int>はfirstは最短距離 secondは頂点番号
	int n = graph.size();
	priority_queue < pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>>que;
	vector<int>d(n, INF);//頂点sからの最短距離
	d[s] = 0;//スタート地点からスタート地点の距離はゼロ
	que.push(pair<int, int>(0, s));
	while (!que.empty()) {
		pair<int, int>p = que.top();
		que.pop();
		int v = p.second;
		for (int i = 0; i < graph[v].size(); i++) {
			edge e = graph[v][i];
			if (d[e.to] > d[v] + e.cost) {
				d[e.to] = d[v] + e.cost;
				que.push(pair<int, int>(d[e.to], e.to));
			}
	    }
	}
	return d;
}

int main() {
	int n;//頂点数
	cin >> n;
	vector<vector<edge>>graph;
	graph.resize(n);
	
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int to, cost;
			cin >> to >> cost;
			edge e;
			e.from = u;
			e.to = to;
			e.cost = cost;
			graph[u].push_back(e);
		}
	}
	vector<int> d=dijkstra(0, graph);
	for (int i = 0; i < n; i++) {
		cout << i << " " << d[i] << endl;
	}

}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include <functional>
#include <iomanip>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <typeinfo>
#define PI 3.14159265359
#define INF 99999999;
#define rep(i, n) for(int i=0; i<n; i++)
#define REP(n) rep(i, n)
#define EPS 1e-10
typedef long long ll;
using namespace std;
typedef pair<int, int> P;

double distanceAB(double xa, double ya, double xb, double yb);
//void trace(int A[], int N);

/*
class Target
{
public:
	vector <string> draw(int n)
	{

	}
};
*/


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];
	
	REP(n)
	{
		d[i] = INFTY;
		color[i] = WHITE;
	}
	
	d[0] = 0;
	color[0] = GRAY;
	while (1)
	{
		minv = INFTY;
		int u = -1;
		REP(n)
		{
			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;
				}
			}
		}
	}
	
	REP(n)
	{
		cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
	}
}


int main()
{
	cin >> n;
	
	rep(i, n) rep(j, n) M[i][j] = INFTY;
	
	int k, c, u, v;
	rep(i, n)
	{
		cin >> u >> k;
		rep(j, k)
		{
			cin >> v >> c;
			M[u][v] = c;
		}
	}
	
	dijkstra();
	
	return 0;
}


/*
void trace(int A[], int N)
{
	REP(N)
	{
		if (i > 0) cout << " ";
		cout << A[i];
	}
	cout << endl;
}
*/


double distanceAB(double xa, double ya, double xb, double yb)
{
	return sqrt((xb-xa)*(xb-xa) + (yb-ya)*(yb-ya));
}

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

#define INF 100000000

#define White 0
#define Gray 1
#define Black 2

//重み付き隣接行列
int Tree[100][100];

//ダイクストラ

void dijkstra(int n){
  int u,minv; 

  //d = 最短コスト
  //p = 頂点vの親
  int d[100], p[100], color[100];

  //初期化

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

  d[0] = 0;
  p[0] = -1;
  color[0] = Gray;

  while(1){
    u = -1;
    minv = INF;

    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;

    //地点の更新

    for(int v = 0 ; v < n ; v++){
      if(color[v] != Black && Tree[u][v] != INF){
	if(d[v] > d[u] + Tree[u][v]){
	  d[v] = d[u] + Tree[u][v];
	  color[v] = Gray;
	}
      }
    }
  }
  for(int i = 0 ; i < n ; i++){
    cout << i << " ";
    if(d[i] == INF){
      cout << -1;
    }else{
      cout << d[i];
    }

    cout << endl;
  }
}

int main(){
  int n;
  int k, c, u, v;
  cin >> n;

  for(int i = 0 ; i < n ; i++){
    for(int j = 0 ; j < n ; j++){
      Tree[i][j] = INF;
    }
  }

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

  dijkstra(n);

  return 0;
}

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

typedef struct{
  int A[1000];
  int ans;
  bool c;
}node;
node T[1000];
int Q[10000000];
int head=0;
int tail=1;
int n;

void function(int num){
  while(true){
    if(head==tail)break;
    num=Q[head++];
    T[num].c=true;
    for(int i=0;i<n;i++){
      if(T[num].A[i]!=0){
	if(T[i].ans>T[num].ans+T[num].A[i]){
	  T[i].ans=T[num].ans+T[num].A[i];
	Q[tail++]=i;
	}
      }
    }
  }
}

int main(){
  int num,son,z,w;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>num>>son;
    T[num].ans=INT_MAX;
    for(int j=0;j<son;j++){
      cin>>z>>w;
      T[num].A[z]=w;
      }
  }
  Q[0]=0;
  T[0].ans=0;
  function(0);
 
  for(int i=0;i<n;i++){
      cout<<i<<" "<<T[i].ans<<endl;
  }
  return 0;
}