Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

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;
}