Go: package main

import (
	"fmt"
	"bufio"
	"os"
	"strconv"
	"container/heap"
)

type Node struct {
	Id int
	Dis int
}

type PriorityQueue []*Node

func (pq PriorityQueue) Len() int { return len(pq) }

func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].Dis < pq[j].Dis
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

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

func (pq *PriorityQueue) Pop() interface{} {
	n := len(*pq)
	pop := (*pq)[n-1]
	*pq = (*pq)[0:n-1]
	return pop
}

func main() {
	var n int
	fmt.Scan(&n)

	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	g := make([][]int, n)
	c := make([][]int, n)
	pq := make(PriorityQueue, 0, n)
	d := make([]int, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		g[u] = make([]int, k)
		c[u] = make([]int, k)
		for j := 0; j < k; j++ {
			sc.Scan()
			g[u][j], _ = strconv.Atoi(sc.Text())
			sc.Scan()
			c[u][j], _ = strconv.Atoi(sc.Text())
		}

		if u == 0 {
			d[u] = 0
		} else {
			d[u] = 1 << 30
		}
		pq.Push(&Node{u, d[u]})
	}
	heap.Init(&pq)

	for pq.Len() > 0 {
		node := heap.Pop(&pq).(*Node)
		for i := 0; i < len(g[node.Id]); i++ {
			nextId := g[node.Id][i]
			nextDis := node.Dis + c[node.Id][i]
			if nextDis < d[nextId] {
				d[nextId] = nextDis
				heap.Push(&pq, &Node{nextId, nextDis})
			}
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		wr.WriteString(strconv.Itoa(i))
		wr.WriteString(" ")
		wr.WriteString(strconv.Itoa(d[i]))
		wr.WriteString("\n")
	}
	wr.Flush()
}

C++: #include <bits/stdc++.h>
#define rep(i, a, b) for(int i = a; i < b; i++)
#define Rep(i, a, b) for(int i = a; i <= b; i++)
#define repr(i, a, b) for(int i = a; i >= b; i--)
#define _GLIBCXX_DEBUG
#define Vl vector<ll>
#define Vs vector<string>
#define Vp vector<pair<ll, ll>>
#define ld long double
using ll = long long;
#define ALL(v) (v).begin(),(v).end()
#define endl "\n"
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define co(x) cout << x << endl
#define coel cout << endl
#define pb push_back
#define sz(v) ((ll)(v).size())
using namespace std;  
const double pi = acos(-1.0);
const ll MOD = 1e9 + 7;
const ll INF = 1LL << 60;
#define pp pair<ll, pair<ll, ll>> 
#define fi first
#define se second

void print(Vl vec){
    rep(i, 0, sz(vec)){
        if(i) cout << " ";
        cout << vec[i];
    }
    coel;
}

////////////////////////////////////////////////////////

// デバッグを消し忘れるな！！！

// dijkstra
// 有向グラフ

const ll mx = 10005;

vector<pair<ll, ll>> adj[mx];
ll d[mx];
ll color[mx];
ll n;

// 頂点0から各頂点vまでの最短経路

void dijkstra(){
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq;
    rep(i, 0, mx) d[i] = INF;
    d[0] = 0;
    color[0] = 1;
    pq.push({0, 0});

    while(!pq.empty()){
        pair<ll, ll> f = pq.top(); pq.pop();
        ll u = f.second; // 番号
        color[u] = 1;
        if(d[u] < f.first) continue;
        rep(j, 0, sz(adj[u])){
            ll v = adj[u][j].first;
            if(color[v])  continue;
            if(d[v] > d[u] + adj[u][j].second){
                d[v] = d[u] + adj[u][j].second;
                pq.push({d[v], v});
            }
        }
    }

    rep(i, 0, n){
        cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl;
    }

}

int main() {
    cin >> n;
    rep(i, 0, n){
        ll u, k; cin >> u >> k;
        rep(j, 0, k){
            ll v, c; cin >> v >> c;
            adj[u].push_back({v, c});
        }
    }

    dijkstra();

    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<stdio.h>
using namespace std;

#define MAX 10001
#define INF 5000001

int a[MAX][MAX];
int n;
int d[MAX];

void Relax(int u, int v){
  if(d[v]> d[u]+a[u][v]){
    d[v]=d[u]+a[u][v];
  
  }
}

void ISS(int s){
  int v;
  for(v=0; v<n; v++){
    d[v]=INF;
  }
  d[s]=0;
}

void Dijkstra(int s){
  int i, v1, v, minv, u; 
  int flag[MAX];
  ISS(s);
  
  for(i=0; i<n; i++) flag[i]=0;

  for(v1=0; v1<n; v1++){
    
      minv = INF;
      // decide u
      for ( i = 0; i < n; i++ ){
          if(flag[i]==1) continue; 
          if(d[i]<=minv){
              u=i;
              minv=d[i];
          }
      }   
      for(v=0; v<n; v++){
          if(a[u][v]==-1) continue;
          if(flag[v]==1) continue;
          /* if(a[u][v]<d[v]){
             d[v]=a[u][v];
             }*/
          Relax(u, v);
      }
      flag[u]=1;
  }
}

int main(){

  int i, j ,u ,k,v,c;
  // int a[MAX][MAX];
  cin>>n;

  for(i=0; i<n; i++){
    for(j=0; j<n; j++){
      a[i][j]=-1;
    }
  }

  for(i=0; i<n; i++){
      cin>>u>>k;
    for(j=0; j<k; j++){
        cin>>v>>c;
        a[i][v]=c;
    }
  }

  /*for(i=0; i<n; i++){
    for(j=0; j<n; j++){
    cout<<a[i][j]<<endl;
    }
    cout<<endl;
    }*/
  Dijkstra(0);
  for(i=0; i<n; i++){
      cout<<i<<" "<<d[i]<<endl;
  }

  return 0;
}