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 <vector>
#include <queue>
using namespace std;
static const int MAX=10000;
static const int INFTY=(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];
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;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
#define N 10000
#define WHITE 0
#define GRAY 1
#define BLACK 2
static const int INFTY = (1<<20);
int n;
vector<pair<int,int> >adj[N];
void dijkstra(void);
int main()
{
  int i,j,k;
  int u, v, c;

  cin >> n;

  for(i = 0;i < n;i++)
  {
    cin >> u >> k;

    for(j = 0;j < k;j++)
    {
      cin >> v >> c;

      adj[u].push_back(make_pair(v, c));
    }
  }

  dijkstra();

  return 0;
}




void dijkstra()
{
  priority_queue<pair<int,int> >PQ;
  int i,j;
  int u,v;
  int d[N],color[N];

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

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

  while(!PQ.empty())
  {
    pair<int,int>a = PQ.top();
    PQ.pop();

    u = a.second;
    color[u] = BLACK;

        if(d[u] < a.first*(-1))
        {
          continue;
        }

        for(j = 0;j < adj[u].size();j++)
        {
          v = adj[u][j].first;

          if(color[v] == BLACK)
          {
    	       continue;
          }

          if(d[v] > d[u] + adj[u][j].second)
          {
    	       color[v] = GRAY;
    	       d[v] = d[u] + adj[u][j].second;
    	       PQ.push(make_pair(d[v]*(-1),v));
          }
        }

      }

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

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,N) for(ll i=0;i<N;++i)
typedef long long int ll;
ll INF = 900010;
static const int white = 0;
static const int gray = 1;
static const int black = 2;
using P = pair<int ,int>;

ll N;
vector<vector<P> > G(10010);

void dijkstra(){
    priority_queue<P, vector<P> , greater<P> > pq;
    vector<int> color(N,white);
    vector<int> d(N,INF);
    d[0] = 0;
    pq.push(make_pair(0,0));
    color[0] = gray;

    while(!pq.empty()){
        P f = pq.top(); pq.pop();
        int u = f.second;
        color[u] = black;

        if(d[u] > f.first ) continue;

        for(auto e : G[u]){
            int v = e.first;
            if( color[v] == black ) continue;
            if(d[v] > d[u] + e.second ){
                d[v] = d[u] + e.second;
                pq.push(make_pair(d[v], v));
                color[v] = gray;
            }
        }
    }

    rep(i,N){
        cout << i << " " << (d[i] == INF ? -1 : d[i] ) << endl;
    }
}

int main(){
    cin >> N;
    rep(j,N){
        ll u,k; cin >> u >> k;
        rep(i,k){
            ll v,c; cin >> v >> c;
            G[u].push_back(make_pair(v,c));
        }
    }

    dijkstra();
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using pii = pair<int, int>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define WHITE 0
#define VISITED 1
#define CANDIDATE 2

void dks(vvpii &g, vi &d, vi &s) {
  priority_queue<pii, vpii, greater<pii>> q;
  q.push(make_pair(d[0], 0));

  while (!q.empty()) {
    auto qt = q.top(); q.pop();
    int u = qt.second, c = qt.first;
    s[u] = VISITED;

    if (d[u] < c) continue;
    
    for (auto cp: g[u]) {
      int v = cp.first, t = d[u] + cp.second;
      if (s[v] != VISITED && t < d[v]) {
        d[v] = t;
        s[v] = CANDIDATE;
        q.push(make_pair(d[v], v)); 
      }
    }
  }
}

int main() {
  int n;
  cin >> n;
  
  vvpii g(n);
  rep(_, n) {
    int u, k;
    cin >> u >> k;

    rep(__, k) {
      int v, c;
      cin >> v >> c;

      g[u].push_back(make_pair(v, c));
    }
  }
  
  vi d(n, 1 << 21), s(n, WHITE);
  d[0] = 0;
  dks(g, d, s);

  rep(i, n) printf("%d %d\n", i, d[i]);
}