Go: package main

import (
	"bufio"
	"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
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

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

#define MAX_VERTEX 100
#define INF 1000000

int vertex_num;   // ???????????°

int cost[MAX_VERTEX][MAX_VERTEX]; // ????????????cost[?§????][??????]??§?§?????????????????????????????????¨???
int d[MAX_VERTEX];                // ????????????d[u]??§?§??????¨u??????????????¢?????¨??????
bool used[MAX_VERTEX];            // ????????????????????£????????¢????±???????????????????

void Input() {
	cin >> vertex_num;

	// (a1) ??\???????????¶??§?????????
	// d??¨cost?????¨???INF
	// used????????????false
	for (int i = 0; i < vertex_num;i++){
		d[i] = INF;
		used[i] = false;
		for (int j = 0; j < vertex_num;j++){
			cost[i][j] = INF;
		}
	}

	for (int i = 0; i < vertex_num; i++) {
		int from, out_num;
		cin >> from >> out_num;
		for (int j = 0; j < out_num; j++) {
			int to, c;
			cin >> to >> c;
			cost[from][to] = c;
		}
	}
}

void Dijkstra() {
	// (b1) ?§????????????????
	d[0] = 0;
	while (true) {
		// ????????????????????¨???
		int vertex = -1;

		// (b2) ????????????????????£????????¢????±??????????????????????
		// ?????????????????????????????????????????§????????¢???????°???????????????¢???
		for (int i = 0; i < vertex_num; i++){
			if (!used[i] && (vertex == -1 || d[i] < d[vertex])){
				vertex = i;
			}
		}

		// ??¨????????????????????????????¨?????????????????????´????????????????????????
		if (vertex == -1) break;

		used[vertex] = true;

		// ???????????¢????¨????????????????
		for (int u = 0; u < vertex_num; u++) {
			d[u] = min(d[u], d[vertex] + cost[vertex][u]);
		}

	}

}

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

int main() {

	Input();
	Dijkstra();
	Output();

	return 0;
}