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<cstdio>
#include<cstring>
#include<queue>
#include<vector>
using namespace std;
const int maxn=10010;
const int Max=10000001;
int n;
int dis[maxn];
bool vis[maxn];

struct edge
{
	int u,v,w;
	edge(int u=0,int v=0,int w=Max):u(u),v(v),w(w){}
};
vector<edge> G[maxn];

struct node
{
	int d,id;
	bool operator < (const node& rhs) const
	{
		return d>rhs.d;
	}
	node(int d=0,int id=0):d(d),id(id){}
};
priority_queue<node> Q;

void dijkstra(int s)
{
	memset(dis,0x7f,sizeof(dis));
	memset(vis,0,sizeof(vis));
	dis[s]=0;
	Q.push(node(0,s));
	while(!Q.empty())
	{
		node u=Q.top();
		Q.pop();
		if(vis[u.id]) continue;
		vis[u.id]=1;
		for(unsigned int i=0;i<G[u.id].size();++i)
		{
			edge e=G[u.id][i];
			if(dis[e.v]>dis[u.id]+e.w)
			{
				dis[e.v]=dis[u.id]+e.w;
				Q.push(node(dis[e.v],e.v));
			}
		}
	}
}

void print()
{
	for(int i=0;i<n;++i)
	  printf("%d %d\n",i,dis[i]);
	return;
}

int main()
{
	scanf("%d",&n);
	for(int i=0;i<n;++i)
	{
		int id,k;
		scanf("%d%d",&id,&k);
		for(int j=0;j<k;j++)
		{
			int v,w;
			scanf("%d%d",&v,&w);
			G[id].push_back(edge(id,v,w));
		}
	}
	dijkstra(0);
	print();
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define vv(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i));
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a), i##_len=(n); i>i##_len; --i)
#define len(x) ((int)(x).size())
#define mp make_pair
#define eb emplace_back
typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
constexpr int MAX = 100;
enum Color { WHITE = 0, GRAY, BLACK };
int n;
vv(int, M, MAX, MAX, INT_MAX);
inline void dijkstra() {
	vi d(MAX, INT_MAX), color(MAX, WHITE);
	d[0] = 0;
	color[0] = GRAY;
	int minv, u;
	while(true) {
		minv = INT_MAX;
		u = -1;
		rep(i, 0, n) {
			if(minv > d[i] && color[i] != BLACK) {
				u = i;
				minv = d[i];
			}
		}
		if(u == -1) break;
		color[u] = BLACK;
		rep(v, 0, n) {
			if(color[v] != BLACK && M[u][v] != INT_MAX && d[v] > d[u] + M[u][v]) {
				d[v] = d[u] + M[u][v];
				color[v] = GRAY;
			}
		}
	}
	rep(i, 0, n) {
		cout << i << " " << (d[i] == INT_MAX ? -1 : d[i]) << endl;
	}
}
int main() {
	cin >> n;
	int u, k, v, c;
	rep(i, 0, n) {
		cin >> u >> k;
		rep(j, 0, k) {
			cin >> v >> c;
			M[u][v] = c;
		}
	}
	dijkstra();
	return 0;
}

C++: #include <iostream>

using namespace std;

#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INFTY 99999999

int color[MAX];
int M[MAX][MAX];
int d[MAX];
int p[MAX];
int n;

int dijkstra(int s)
{

	int mincost;
	int u;

	for (int i = 0; i < n; i++) {
		d[i] = INFTY;
		p[i] = -1;
	}
	d[s] = 0;

	while (true) {
		mincost = INFTY;

		for (int i = 0; i < n; i++) {
			if (color[i] != BLACK&&d[i] < mincost) {
				mincost = d[i];
				u = i;
			}
		}

		if (mincost == INFTY) {
			break;
		}

		color[u] = BLACK;

		for (int i = 0; i < n; i++) {
			if (color[i] != BLACK&&M[u][i] != INFTY) {
				if (d[u] + M[u][i] < d[i]) {
					d[i] = d[u] + M[u][i];
					p[i] = u;
					color[i] = GRAY;
				}
			}
		}


	}


	int sum = 0;

	for (int i = 0; i < n; i++) {
		sum += d[i];
	}

	return sum;


}

int main(void)
{

	cin >> n;

	int u;
	int k;
	int v;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = INFTY;
		}
	}


	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			cin >> M[u][v];
		}
	}

	dijkstra(0);

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

	return 0;
}