Go: package main

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

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	list := make([][]int, n)
	weight := make([]int, n)
	for i := range list {
		list[i] = make([]int, n)
		weight[i] = NIL
		for j := range list[i] {
			list[i][j] = NIL
		}
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			v := scanInt()
			w := scanInt()
			list[u][v] = w
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for i, w := range list[node.id] {
			if w == NIL {
				continue
			}
			heap.Push(h, Node{id: i, weight: w + node.weight})
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, weight[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #define _USE_MATH_DEFINES
#include<iostream>
#include<algorithm>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<deque>
#include<queue>
#include<map>
#include<set>
#define ll long long
#define str string
#define ld long double
#define vec vector
#define vll vec<ll>
#define rep(i,a,b) for(ll i=a;i<b;i++)
#define rrep(i,b,a) for(ll i=b;i>=a;i--)
#define ALL(a) a.begin(),a.end()
#define rALL(a) a.rbegin(),a.rend()
#define kai "\n"
#define yuque priority_queue
#define ryuque(t) priority_queue<t,vec<t>,greater<t>>
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define mie min_element
#define mae max_element
#define tos to_string
#define sep setprecision
#define MOD 1000000007ll
using namespace std;
void solve();
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed;
	solve();
}

//nCk(mod p)
const ll NUM = 2;
ll fac[NUM], finv[NUM], inv[NUM];
void cmodf(ll p = MOD) {
	fac[0] = fac[1] = 1;
	finv[0] = finv[1] = 1;
	inv[1] = 1;
	rep(i, 2, NUM) {
		fac[i] = fac[i - 1] * i%p;
		inv[i] = p - inv[p%i] * (p / i) % p;
		finv[i] = finv[i - 1] * inv[i] % p;
	}
}
ll cmod(ll n, ll k, ll p = MOD) {
	return fac[n] * (finv[k] * finv[n - k] % p) % p;
}

//最大公約数
ll gcd(ll n, ll m) {
	ll k = n % m;
	while (k != 0) { n = m; m = k; k = n % m; }
	return m;
}
ll gcd(vector<ll> a) {
	rep(i, 1, a.size()) {
		ll k = a[i - 1] % a[i];
		while (k != 0) {
			a[i - 1] = a[i];
			a[i] = k;
			k = a[i - 1] % a[i];
		}
	}
	return a.back();
}

//最小公倍数
ll lcm(ll n, ll m) {
	ll t = n * m, k = n % m;
	while (k != 0) { n = m; m = k; k = n % m; }
	return t / m;
}
ll lcm(vector<ll> a) {
	ll n;
	rep(i, 1, a.size()) {
		n = a[i - 1] * a[i];
		ll k = a[i - 1] % a[i];
		while (k != 0) {
			a[i - 1] = a[i];
			a[i] = k;
			k = a[i - 1] % a[i];
		}
		n /= a[i];
		a[i] = n;
	}
	return n;
}

//keyの小さい方から探していった時に初めてvalueがjoken以上になる時のkey（keyが増えたらvalueも増えるか同じになるとき）
ll value(ll key) {
	/*変更*/
	return 0;
}
ll mink(ll lkey, ll rkey/*ここも調べる*/, ll joken) {
	ll mkey;
	while (lkey != rkey) {
		mkey = (lkey + rkey) / 2;
		if (value(mkey) >= joken)rkey = mkey;
		else lkey = mkey + 1;
	}
	return rkey;
}

//ペア配列の整理
struct pea {
	ll f, s;
	bool operator<(const pea &c)const {
		return f != c.f ? f < c.f : s < c.s;
	};
};

//変数定義

//再帰関数

//アルゴリズム
void solve() {
	ll n; cin >> n;
	vec<vll> a(n, vll(n, MOD));
	rep(i, 0, n) {
		ll u, k; cin >> u >> k;
		rep(j, 0, k) {
			ll v, c; cin >> v >> c;
			a[u][v] = c;
		}
	}
	vll ans(n), p;
	ans[0] = 0;
	p.pub(0);
	rep(i, 0, n)a[i][0] = MOD;
	while (p.size() != n) {
		ll m = MOD, jj;
		rep(i, 0, p.size())rep(j, 0, n)if (ans[p[i]] + a[p[i]][j] < m) {
			m = a[p[i]][j] + ans[p[i]];
			jj = j;
		}
		p.pub(jj);
		ans[jj] = m;
		rep(i, 0, n)a[i][jj] = MOD;
	}
	rep(i, 0, n)cout << i << " " << ans[i] << kai;
}

C++: #include<vector>
#include<iostream>
#include<algorithm>
#define MAX_V 100
#define INF 1e9
using namespace std;
int V;
int d[MAX_V];
int cost[MAX_V][MAX_V];
bool used[MAX_V];

void dijkstra(int s)
{
	d[s] = 0;
	while (true)
	{
		int v = -1;
		for (int u = 0; u < V; u++)
		{
			if (!used[u] && (v == -1 || d[u] < d[v]))
			{
				v = u;
			}
		}
		if (v == -1)
		{
			break;
		}
		used[v] = true;

		for (int u = 0; u < V; u++)
		{
			//if (cost[v][u] = INF)
			//{
			//	continue;
			//}
			d[u] = min(d[u], d[v] + cost[v][u]);
		}
	}

}
int main()
{
	cin >> V;
	for (int i = 0; i < MAX_V; i++)
	{
		for (int j = 0; j < MAX_V; j++)
		{
			cost[i][j] = INF;
		}
	}
	for (int i = 0; i < MAX_V;i++)
	{
		d[i] = INF;
		used[i] = false;
	}
	for (int i = 0; i < V; i++)
	{
		int u;
		cin >> u;
		int k;
		cin >> k;
		for (int j = 0; j < k; j++)
		{
			int v_to;
			cin >> v_to;
			int c;
			cin >> c;

			cost[u][v_to] = c;

		}
	}

	dijkstra(0);

	for (int i = 0; i < V; i++)
	{
		cout << i << " " << d[i] << endl;
	}

	return 0;

}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)   for(int i=0;i<(n);++i)
#define SORT(c)    sort((c).begin(),(c).end())
#define CLR(a)     memset((&a), 0 ,sizeof(a))//clear memory
#define dump(x)    cerr << #x << " = " << (x) << endl;//debug
#define debug(x)   cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#define EPS        1e-10//sample:if((double)>=(double)+EPS)
//cin,cout release
//std::cin.tie(0);
//ios::sync_with_stdio(false);

using namespace std;
int n;
int d[100000];
int color[100000];
vector<pair<int,int> > adj[100000];
#define WHITE 0
#define BLACK 2
#define GRAY 1
void dijkstra(){
  rep(i,n)d[i]=INT_MAX;
  priority_queue< pair<int,int> > PQ;
  rep(i,n)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;
    rep(j,(int)adj[u].size()){
      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;
      }
    }
  }
  rep(i,n)cout<<i<<" "<<(d[i]==INT_MAX?-1:d[i])<<endl;
}


int main(){
  int a,b,c,d;
  cin>>n;
  rep(i,n){
    cin>>a>>b;
    rep(j,b){
      cin>>c>>d;
      adj[a].push_back(make_pair(c,d));
    }
  }
  dijkstra();
  return 0;
}