Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const (
	INFTY = 1 << 21
	NIL   = -1
)

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph [][]int

func (g *Graph) dikstra(n int) string {
	var (
		u, minv = 0, 0
	)

	d := make([]int, n)
	color := make([]int, n)

	for i := 0; i < n; i++ {
		d[i] = INFTY
		color[i] = WHITE
	}
	d[0] = 0
	color[0] = GRAY

	for {
		minv = INFTY
		u = -1
		for i := 0; i < n; i++ {
			if minv > d[i] && color[i] != BLACK {
				u = i
				minv = d[i]
			}
		}

		if u == -1 {
			break
		}

		color[u] = BLACK
		for v := 0; v < n; v++ {
			if color[v] != BLACK && (*g)[u][v] != INFTY {
				if d[v] > d[u]+(*g)[u][v] {
					d[v] = d[u] + (*g)[u][v]
					color[v] = GRAY
				}
			}
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d ", i))
		if d[i] == INFTY {
			out.WriteString(fmt.Sprintf("%d\n", -1))
			continue
		}
		out.WriteString(fmt.Sprintf("%d\n", d[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	g := make(Graph, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for j := 0; j < n; j++ {
			g[i][j] = INFTY
		}
	}

	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())

		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			sc.Scan()
			c, _ := strconv.Atoi(sc.Text())

			g[u][v] = c
		}
	}

	return g.dikstra(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include <cstdio>
#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
#include <set>
#include <map>
#include <deque>
#define NMAX 100
#define INF 100000000

//??????????????¢??????????????¨debug()??????????????????
#define DEBUG

using namespace std;
template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
    std::fill( (T*)array, (T*)(array+N), val );
}

typedef pair<int ,int > P;
typedef long long ll;

int N,ans = 0;
int d[NMAX] = {};
vector<P> connect[NMAX];

void solve(){
	d[0] = 0;
	priority_queue<P, vector<P>, greater<P> > que;
	que.push(P(0,0));
	while(!que.empty()){
		P p = que.top();
		// cout << "P(" << p.first << "," << p.second << ")\n";
		que.pop();
		int v = p.first;
		if(d[v] < p.second) continue;
		for (int i = 0; i < connect[v].size(); ++i)
		{
			if(d[connect[v][i].first] > d[v] + connect[v][i].second){
				d[connect[v][i].first] = d[v] + connect[v][i].second;
				que.push(P(connect[v][i].first,d[connect[v][i].first]));
			}
		}
	}
}

void debug(){

}

void answer(){
	for (int i = 0; i < N; ++i)
	{
		cout << i << " " << d[i] << "\n";
	}
}

int main(){
	cin >> N;
	for (int i = 0; i < N; ++i)
	{
		int a,b;
		cin >> a >> b;
		for (int j = 0; j < b; ++j)
		{
			int k,l;
			cin >> k >> l;
			connect[a].push_back(P(k,l));
		}
	}
	Fill(d,INF);
	solve();
	#ifdef DEBUG
	debug();
	#endif
	answer();

	return 0;
}