Go: package main

import (
	"bufio"
	"container/heap"
	"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
const INF = 1 << 60

type Edge struct {
	to, cost int
}

type Node struct {
	id, cost int
}

type PQ []Node

func (pq PQ) Len() int           { return len(pq) }
func (pq PQ) Less(i, j int) bool { return pq[i].cost < pq[j].cost }
func (pq PQ) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }

func (pq *PQ) Push(x interface{}) {
	*pq = append(*pq, x.(Node))
}

func (pq *PQ) Pop() interface{} {
	old := *pq
	n := len(old)
	x := old[n-1]
	*pq = old[0 : n-1]
	return x
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		E[id] = make([]Edge, k)
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id][j] = Edge{to, cost}
		}
	}

	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	done := make([]bool, N)
	pq := &PQ{}
	heap.Init(pq)
	d[0] = 0
	heap.Push(pq, Node{0, 0})
	for pq.Len() > 0 {
		cur := heap.Pop(pq).(Node).id
		if done[cur] {
			continue
		}
		done[cur] = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+d[cur]
			if !done[to] && cost < d[to] {
				d[to] = cost
				heap.Push(pq, Node{to, cost})
			}
		}
	}

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

C++: //
// Created by ?????°?????? on 2016/05/19.
//

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

int n;
vector<pair <int,int> > adj[MAX];

void dijkstra(){
    priority_queue< pair<int,int> > PQ;
    int color[MAX];
    int d[MAX];
    for (int i = 0; i < n ; ++i) {
        d[i] = INFTY ;
        color[i] = WHITE;
    }

    d[0] = 0;
    PQ.push(make_pair(0,0));
    color[0] = GRAY;

    while ( !PQ.empty() ){
        pair <int,int> f = PQ.top(); PQ.pop();
        int u = f.second;
        color[u] = BLACK;

        if(d[u] < f.first * -1) continue;

        for (int j = 0; j < adj[u].size() ; ++j) {
            int v = adj[u][j].first;
            if (color[v] == BLACK) continue;
            if (d[v] > d[u] + adj[u][j].second){
                d[v] = d[u] + adj[u][j].second;
                PQ.push(make_pair(d[v]*(-1),v));
                color[v] = GRAY;
            }
        }
    }


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

int main (){
    cin >> n;
    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;
            adj[u].push_back(make_pair(v,c));
        }
    }

    dijkstra();

    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(long long i=0; i<(n); i++)
#define int long long
#define mod 1000000007
#define F first
#define S second
#define P pair<long long,long long>
#define all(a) a.begin(),a.end()
#define INF 1000000000000000000
using namespace std;
struct edge{
    long long to;
    long long cost;
};
signed main(void){
    int n;cin>>n;
    vector<edge>G[n];
    int f,t,c,k;
    rep(i,n){
        cin>>f>>k;
        rep(j,k){
            cin>>t>>c;
            G[f].push_back({t,c});
        }
    }
    vector<int>d(n,INF);d[0]=0;
    //rep(i,n){
      //  rep(j,G[i].size()){
        //    cout<<G[i][j].to<<':'<<G[i][j].cost<<' ';
        //}
        //cout<<endl;
    //}
    priority_queue<P,vector<P>,greater<P>>que;
    que.push(P(0,0));
    while(!que.empty()){
        f=que.top().S;c=que.top().F;que.pop();
        if(d[f]<c)continue;
        rep(i,G[f].size()){
            edge e=G[f][i];
            t=e.to;
            if(d[t]>e.cost+c){
                d[t]=e.cost+c;
                que.push(P(d[t],t));
            }
        }
    }
    rep(i,n){
        cout<<i<<' '<<d[i]<<endl;
    }
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <vector>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1<<21);

enum Color {
  WHITE, GRAY, BLACK
};

vector<pair<int, int> > adj[MAX];
int d[MAX];
Color color[MAX];
int n;

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

void dijkstra(int s) {
  init();
  d[s] = 0;
  priority_queue<pair<int, int> > PQ;
  PQ.push(make_pair(0, s));

  while (!PQ.empty()) {
    pair<int, int> f = PQ.top(); PQ.pop();
    int u = f.second;
    color[u] = BLACK;

    if (d[u] < f.first * (-1)) continue;

    for (int j = 0; j < adj[u].size(); j++) {
      int v = adj[u][j].first;
      if (color[v] == BLACK) continue;
      if (d[u] + adj[u][j].second < d[v]) {
        d[v] = d[u] + adj[u][j].second;
        PQ.push(make_pair(d[v] * (-1), v));
        color[v] = GRAY;
      }
    }
  }
}


int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    int elem, index, v;
    cin >> v >> elem;
    for (int j = 0; j < elem; j++) {
      int u, cost;
      cin >> u >> cost;
      adj[v].push_back(make_pair(u, cost));
    }
  }
  dijkstra(0);
  for (int i = 0; i < n; i++) {
    cout << i << " " << d[i] << endl;
  }
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1<<20);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int,int> > adj[MAX];

void dijkstra(){
  priority_queue<pair<int,int> > PQ;
  int color[MAX];
  int d[MAX];
  for(int i = 0; i<n;i++){
    d[i] = INFTY;
    color[i] = WHITE;
  }

  d[0] = 0;
  PQ.push(make_pair(0,0));
  color[0] = GRAY;

  while(!PQ.empty()){
    pair<int,int> f = PQ.top();
    PQ.pop();
    int u = f.second;
    color[u] = BLACK;

    if(d[u]<f.first * (-1)) continue;

    for(int j = 0; j<adj[u].size(); j++){
      int v = adj[u][j].first;
      if(color[v] == BLACK) continue;
      if(d[v]>d[u]+adj[u][j].second){
	d[v] = d[u]+adj[u][j].second;
	PQ.push(make_pair(d[v]*(-1),v));
	color[v] = GRAY;
      }
    }
  }
  for(int i = 0; i < n; i++){
    cout << i<<" "<<(d[i] == INFTY?-1:d[i])<<endl;
  }
}

int main(){
  int k,u,v,c;

  cin>>n;
  for(int i = 0; i<n; i++){
    cin>>u>>k;
    for(int j = 0; j<k; j++){
      cin>>v>>c;
      adj[u].push_back(make_pair(v,c));
    }
  }
  dijkstra();
  return 0;
}