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++: #include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
 
#define MAX   10000
#define INFTY (1 << 20)
#define WHITE 0
#define GRAY  1
#define BLACK 2
 
int n;
vector<pair<int, int> > adj[MAX];
 
void dijkstra() {
  priority_queue<pair<int, int> > PQ;
  int color[MAX], d[MAX];
  for ( int i = 0; i < n; i++ ) {
    color[i] = WHITE;
    d[i] = INFTY;
  }
 
  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 u, k, c, v;
  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;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<queue>
#include<vector>
#include<stack>
using namespace std;
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INFTY (1<<30)
int n;
vector<pair<int,int> > adj[MAX];

void dijkstra()
{
  priority_queue<pair<int,int> > PQ;
  int d[MAX],color[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<stdio.h>
#include<iostream>
#include<algorithm>
#include<string>
#include<string.h>
#include<math.h>
#include<stdlib.h>
#include<vector>
#include<queue>
#include<map>
#define rep(index,num) for(int index=0;index<num;index++)
#define rep1(index,num) for(int index=1;index<=num;index++)
#define scan(argument) cin>>argument
#define prin(argument) cout<<argument<<endl
#define kaigyo cout<<endl
#define eps 1e-15
#define mp(a1,a2) make_pair(a1,a2)
typedef long long ll;
using namespace std;
typedef pair<int,int> pint;
typedef vector<int> vint;
typedef vector<pint> vpint;
int INF=1e+9+1;
int N;
vpint adj[10000];
int d[100],color[100],p[100];
void dijkstra(){
	priority_queue<pint> PQ;
	rep(i,N){
		d[i]=INF;
		color[i]=0;
	}
	d[0]=0;
	color[0]=1;
	PQ.push(mp(0,0));
	while(!PQ.empty()){
		pint f=PQ.top();
		PQ.pop();
		int u=f.second;
		color[u]=2;
		if(d[u]< -f.first) continue;
		rep(j,adj[u].size()){
			int v=adj[u][j].first;
			if(color[v]==2) continue;
			if(d[v]>d[u]+adj[u][j].second){
				d[v]=d[u]+adj[u][j].second;
				PQ.push(mp(-d[v],v));
				color[v]=1;
			}
		}
	}
}
int main(){
	scan(N);
	int k,c,u,v;
	rep(i,N){
		scan(u);scan(k);
		rep(j,k){
			scan(v);scan(c);
			adj[u].push_back(mp(v,c));
		}
	}
	dijkstra();
	rep(i,N){
		printf("%d %d\n",i,(d[i]==INF ? -1 : d[i]));
	}
	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;
}