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

const int Max = 10000;
const int Infty = (1 << 21);
const int white = 0, gray = 1, black = 2;

int d[Max], color[Max];
int n;

vector<pair<int, int> > adj[Max];

void dijkstra(int s){
    priority_queue<pair<int, int> > PQ;
    for(int i=0; i<n; i++){
        d[i] = Infty;
        color[i] = white;
    }
    d[s] = 0;
    color[s] = gray;
    PQ.push(make_pair(0, 0)); //(d[u], u) u:be adjacent to s

    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[u] + adj[u][i].second < d[v]){
                d[v] = d[u] + adj[u][i].second;
                color[v] = gray;
                PQ.push(make_pair(d[v] * (-1), v));
            }
        }
    }
    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 >> n >> k;
        for(int j=0; j<k; j++){
            cin >> v >> c;
            adj[u].push_back(make_pair(v, c));
        }
    }

    dijkstra(0);

    return 0;
}

C++: /#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
typedef long long ll;

map <int,int> mp;

#define INF (1<<30)
#define INFLL (1ll<<60)
#define EPS (1e-10)
static const int MAX=1e5;
static const int MOD=1e9+7;
static const int NMAX=50;
static const int MMAX=50;
int dx[4]={0,1,0,-1},dy[4]={-1,0,1,0};

typedef pair<int, int> P; //最短距離,頂点の番号
struct edge{
    int to,cost;
};
int N;
vector<edge> G[MAX]; //
int d[MAX]; //最短距離

void dijkstra(int s){
    priority_queue<P, vector<P>,greater<P> > que;
    
    fill(d,d+N,INF);
    d[s]=0;
    que.push(P(0,s));
    
    while(!que.empty()){
        P p=que.top(); que.pop();
        int v=p.second;
        
        if(d[v] < p.first) continue;
        for(int i=0;i<G[v].size();i++){
            edge e=G[v][i];
            if(d[e.to]>d[v]+e.cost){
                d[e.to] =d[v]+e.cost;
                que.push(P(d[e.to],e.to));
            }
        }
    }
}


int main(){
    cin.tie(0);  ios::sync_with_stdio(false);
    
    int k,u;
    cin>>N;
    for(int i=0;i<N;i++){
        cin>>u>>k;
        for(int j=0;j<k;j++){
            edge e;
            cin>>e.to>>e.cost;
            G[u].push_back(e);
        }
    }
    dijkstra(0);
    for(int i=0;i<N;i++)
        cout<<i<<" "<<(d[i]==INF?-1:d[i])<<"\n";
    
    return 0;
    }

C++: #include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1 << 20);
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 <bits/stdc++.h>

using namespace std;

vector<int> adja[10000], cost[10000];

#define INF (1 << 30)

int main() {
	int n, id, k;

	cin >> n;
	for (int i = 0; i < n; ++i) {
		cin >> id >> k;
		adja[id].resize(k);
		cost[id].resize(k);
		for (int j = 0; j < k; ++j) {
			cin >> adja[id][j] >> cost[id][j];
		}
	}

	priority_queue<pair<int, int>> que;
	que.push(make_pair(0, 0)); //cost, node
	int best[10000];
	fill(best, best + n, INF);
	best[0] = 0;

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

		for (int j = 0, len = adja[top.second].size(); j < len; ++j) {
			if (best[adja[top.second][j]] > top.first + cost[top.second][j]) {
				best[adja[top.second][j]] = top.first + cost[top.second][j];
				que.push(make_pair(top.first + cost[top.second][j], adja[top.second][j]));
			}
		}
	}

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

	return 0;
}