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<climits>
#include<vector>
#include<list>
#include<functional>
#include<algorithm>
#include<string>
#include<cmath>
#include<complex>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define INF (int)1e9
#define INFL (ll)1e11
using namespace std;
typedef long long ll;
typedef pair<int, int> P;

void dijkstra(vector<vector<int>> v, vector<vector<int>> c, vector<int> &d) {
	d[0] = 0;
	priority_queue<P, vector<P>, greater<P>> pq;
	pq.push(P(0, 0));
	while (!pq.empty()) {
		int s = pq.top().second;
		int dis = pq.top().first;
		pq.pop();
		if (dis > d[s]) continue;
		REP(j, v[s].size()) {
			int u = v[s][j];
			int w = c[s][j];
			if (d[u] > d[s] + w) {
				d[u] = d[s] + w;
				pq.push(P(d[u], u));
			}
		}
	}
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int n;
	cin >> n;
	vector<vector<int>> v(n), c(n);
	REP(i, n) {
		int u, k;
		cin >> u >> k;
		v[u] = vector<int>(k);
		c[u] = vector<int>(k);
		REP(j, k) cin >> v[u][j] >> c[u][j];
	}
	vector<int> d(n, INF);
	dijkstra(v, c, d);
	REP(i, n) {
		cout << i << " " << d[i] << "\n";
	}
	
	return 0;
}

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

#define N_MAX 100

typedef pair<int, int> node;
typedef vector<node> Adj_list;
typedef vector<Adj_list> Adj_lists;

class less_cost{
public:
  bool operator()(const pair<int, int> lhs, const pair<int, int> rhs) const{
    return lhs.second < rhs.second;
  }
};

int main(){

  int n;
  scanf("%d", &n);

  Adj_lists adj_lists(n);

  // read weigts
  for(int i=0; i<n; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    for(int j=0; j<k; j++){
      int v,c;
      scanf("%d %d", &v, &c);
      adj_lists.at(u).push_back(node(v, c));
    }
  }

  // initialize cost
  priority_queue<node, vector<node>, less_cost> pq;
  pq.push(node(0, 0));
  vector<int> d(n, INT_MAX);
  d.at(0) = 0;

  //dijkstra's algorithm
  while(!pq.empty()){
    // extract node u in V-S that has minimum cost
    node u = pq.top();
    pq.pop();

    // if u's cost is larger than d[u],
    // than ignore this one
    if(u.second < d.at(u.first)) continue;

    // update node in V-S and adjacent to u
    for(const node& v : adj_lists.at(u.first)){
      if(d[u.first] + v.second < d[v.first]){
        d[v.first] = d[u.first] + v.second;
        pq.push(node(v.first, d[v.first]));
      }
    }
  }

  // output
  for(int i=0; i<n; i++){
    printf("%d %d\n", i, d[i]);
  }

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<queue>
#include<algorithm>

#define MAX 10000

using namespace std;

int n;
int unvisited=0,visited=1,comp_visited=2;
int INFTY=(1<<20);
vector<pair<int,int> > adj[MAX];

void dijkstra(){
	priority_queue<pair<int,int> > PQ;
	int state[MAX];
	int d[MAX];
	for(int i=0;i<n;i++){
		d[i]=INFTY;
		state[i]=unvisited;
	}
	d[0]=0;
	PQ.push(make_pair(0,0));
	state[0]=visited;
	while(!PQ.empty()){
		pair<int,int> f = PQ.top(); PQ.pop();
		int u=f.second;
		state[u]=comp_visited;
		
		//????°??????????????????????, ?????????????????§???????????°????????????.
		if(d[u]<f.first*(-1)) continue;
		
		for(int j=0;j<adj[u].size();j++){
			int v=adj[u][j].first;
			if(state[v]==comp_visited) 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));
				state[v]=visited;
			}
		}
	}
	for(int	i=0;i<n;i++){
		printf("%d %d\n",i,(d[i]==INFTY ? -1:d[i]));
	}
}

int main(){
	int k,u,v,c;
	
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		for(int j=0;j<k;j++){
			scanf("%d %d",&v,&c);
			adj[u].push_back(make_pair(v,c));
		}
	}
	dijkstra();
}

C++: //ALDS1_12C
#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
 
static const int MAX=10000;
static const int INF=(1<<21);
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;
 
int n;
vector<pair<int,int> > adj[MAX];
 
int dijkstra(){
 priority_queue<pair<int,int> > PQ;
 int d[MAX],color[MAX];
 for(int i=0;i<n;i++){
  d[i]=INF;
  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]==INF ? -1:d[i])<<endl;
 }
} 
 
int main(){
 int k,c,u,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;
}