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<bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i = 0; i < n; i++)
#define Rep(i,n) for(int i = 1; i <= n; i++)
#define sz(x) int(x.size())
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define YesorNo(a) printf(a ? "Yes\n" : "No\n")
#define endl '\n'
#define fi first
#define se second
using ll = long long;
using P = pair<int,int>;
using Pl = pair<ll,ll>;
template<class T> using V = vector<T>;
const int dx[] = {0,1,0,-1,1,1,-1,-1};
const int dy[] = {1,0,-1,0,1,-1,-1,1};
const int inf = (1<<30)-1;
const ll infll = (1LL<<62)-1;
ll ceil(const ll &a, const ll &b){return ((a)+(b)-1)/b;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }


void Dijkstra(int s, const vector<vector<P>> &g, vector<int> &dis) {
  priority_queue<P, vector<P>, greater<P>> que; // pair = (cost, v);
  dis[s] = 0;
  que.emplace(0,s);
  while(!que.empty()) {
    P p = que.top(); que.pop();
    int now = p.second;
    if(dis[now] < p.first) continue;
    for(P np : g[now]) {
      int next = np.second;
      if(dis[next] > dis[now] + np.first) {
        dis[next] = dis[now] + np.first;
        que.emplace(dis[next], next);
      }
    }
  }
}


int main(){
    
    int n;
    cin >> n;
    V<V<P>> g(n); // pair = (cost, to);
    rep(i,n) {
        int a, k;
        cin >> a >> k;
        rep(j,k) {
            int b, v;
            cin >> b >> v;
            g[a].emplace_back(v,b);
        }
    }

    V<int> d(n, inf);
    Dijkstra(0,g,d);
    rep(i,n) {
        printf("%d %d\n", i, d[i]);
    }
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <climits>
#include <queue>

#define INF INT_MAX

using namespace std;

int main(){
  int n; cin >> n;
  vector<pair<int,int> > G[n];
  for(int i=0;i<n;i++){
    int u,k; cin >> u >> k;
    for(int j=0;j<k;j++){
      int v,c; cin >> v >> c;
      G[u].push_back(make_pair(v,c));
    }
  }
  //dijkstra from 0
  priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > PQ;
  int visited[n],d[n];
  for(int i=0;i<n;i++){
    visited[i]=0;
    d[i]=INF;
  }
  d[0]=0;
  PQ.push(make_pair(d[0],0));
  while(PQ.empty()==false){
    int u=PQ.top().second;
    int u_first=PQ.top().first;
    PQ.pop();
    //cout << "u:" << u << endl;
    visited[u]=1;
    if(d[u]<u_first) continue;
    for(int i=0;i<G[u].size();i++){
      int v=G[u][i].first;
      //cout << "v:" << v << endl;
      if(visited[v]==0){
        if(d[u]+G[u][i].second<d[v]){
          d[v]=d[u]+G[u][i].second;
          PQ.push(make_pair(d[v],v));
        }
      }
    }
  }
  for(int i=0;i<n;i++) cout << i << " " << d[i] << endl;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#define MAX 10000
#define INF (1 << 21)
#define WHITE  1
#define GRAY  2
#define BLACK  3
using namespace std;

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

void dijkstra(){
  priority_queue<pair<int, int> > pq;

  vector<int> color(MAX);
  vector<int> d(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 i = 0; i < adj[u].size(); i++){
      int v = adj[u][i].first;

      if(color[v] == BLACK) continue;
      if(d[v] > d[u] + adj[u][i].second){
	d[v] = d[u] + adj[u][i].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, 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;

}