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 <iostream>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;

const int MAX = 10000;
const int INF = 1e9 + 7;

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

void dijkstra()
{
  int d[MAX], color[MAX];
  priority_queue<pair<int, int> > pq;

  fill(d, d + MAX, INF);
  fill(color, color + MAX, 0);

  d[0] = 0;
  pq.push(make_pair(0, 0));
  color[0] = 1;

  while (!pq.empty()) {
    pair<int, int> f = pq.top();
    pq.pop();
    int u = f.second;
    color[u] = 2;

    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] == 2) 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] = 1;
      }
    }
  }
  
  for (int i = 0; i < n; i++) 
    cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl;
  }
}

signed 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<algorithm>
#include<queue>
#define MAX 10000
int INF=(1<<20), WH=0, GR=1, BL=2;
int n;
std::vector<std::pair<int,int> > adj[MAX];
void dij(void);
int main(){
  int k, u, v, c;
  std::cin >> n;
  for(int i=0; i<n; i++){
    std::cin >> u >> k;
    for(int j=0; j<k; j++){
      std::cin >> v >> c;
      adj[u].push_back(std::make_pair(v,c));
    }
  }
  dij();
  return 0;
}
void dij(void){
  std::priority_queue<std::pair<int,int> > PQ;
  int color[MAX], d[MAX];
  for(int i=0; i<n; i++) d[i] = INF, color[i] = WH;
  d[0] = 0;
  PQ.push(std::make_pair(0,0));
  color[0] = GR;
  while(!PQ.empty()){
    std::pair<int,int> f=PQ.top(); PQ.pop();
    int u=f.second;
    color[u] = BL;
    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] == BL) continue;
      if(d[v] > d[u] + adj[u][j].second){
	d[v] = d[u] + adj[u][j].second;
	PQ.push(std::make_pair(d[v]*(-1),v));
      }
    }
  }
  for(int i=0; i<n; i++) std::cout << i << " " << (d[i] == INF ? -1 : d[i]) << std::endl;
}

C++: /**
 *      purpose : 
 *      author  : kyomukyomupurin
 *      created : 
**/

// input/output
#include <fstream>
#include <iostream>
#include <sstream>
// container class
#include <array>
#include <deque>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>
// math, algorithm
#include <algorithm>
#include <cmath>
#include <complex>
#include <numeric>
// etc
#include <bitset>
#include <cassert>
#include <cctype>
#include <cstring>
#include <chrono>
#include <functional>
#include <iomanip>
#include <random>
#include <utility>
// using-directive
using namespace std;
// alias template
using int64 = long long;
using uint64 = unsigned long long;
using vi = std::vector<int>;
using vl = std::vector<int64>;
using pii = std::pair<int, int>;
using pii = std::pair<int, int>;
using pll = std::pair<int64, int64>;
// text macro replacement
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(_) (_).begin(), (_).end()
#define rall(_) (_).rbegin(), (_).rend()
#define print(_) std::cout << (_) << '\n'
#define debug(_) std::cerr << #_ << ": " << (_) << '\n'
#define dbg(vec) for (size_t _ = 0; _ < vec.size(); ++_){std::cerr << #vec << "[" << _ << "] : " << vec[_] << '\n';}
// variadic template
template<typename T> inline void chmin(T &a, T b) {if (a > b) a = b; return;}
template<typename T> inline void chmax(T &a, T b) {if (a < b) a = b; return;}
// constant
const int INF = (1<<30) - 1;  // 1.073741823e9
const int64 INF64 = (1LL<<62) - 1;  // 4.611686018427387903e18
const int MOD = 1000000007;

const int MAX_V = 101010;
//const int64 INF64 = (1LL<<62) - 1;

struct edge {
  int64 to, cost;
};

int n;
std::vector<edge> G[MAX_V];
int64 dis[MAX_V];

void dijkstra(int s){
  std::priority_queue<std::pair<int64, int64>,
                      std::vector<std::pair<int64, int64>>,
                      std::greater<std::pair<int64, int64>>> pq;
  std::fill(dis, dis + n, INF64);
  dis[s] = 0;
  pq.push(std::pair<int64, int64>(0, s));

  while (!pq.empty()){
    std::pair<int64, int64> p = pq.top(); pq.pop();
    int v = p.second;
    if (dis[v] < p.first) continue;
    for (size_t i = 0; i < G[v].size(); ++i){
      edge e = G[v][i];
      if (dis[e.to] > dis[v] + e.cost){
        dis[e.to] = dis[v] + e.cost;
        pq.emplace(std::pair<int64, int64>(dis[e.to], e.to));
      }
    }
  }
}

int main(){
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(nullptr);

  cin >> n;
  for (int i = 0; i < n; ++i) {
    int u, k; cin >> u >> k;
    for (int j = 0; j < k; ++j) {
      int64 v, c; cin >> v >> c;
      G[u].push_back({v, c});
    }
  }

  dijkstra(0);

  for (int i = 0; i < n; ++i) {
    cout << i << " " << dis[i] << '\n';
    //if (i != n - 1) cout << '\n';
  }

  return 0;
}