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<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
int main() {
	int n, u, k, v, c, i, j, d[100][100], m[100][100], o, p[100] = { 0 }, e, q = 0;
	memset(m, 0x7f, sizeof(m));
	memset(d, 0x7f, sizeof(d));
	d[0][0] = 0;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> u >> k;
		for (j = 0; j < k; j++) {
			cin >> v >> c;
			m[u][v] = c;
		}
	}
	p[0] = 1;
	for (i = 1; i < n; i++) {
		o = d[0][n - 1];
		for (j = 0; j < n; j++) {
			d[i][j] = min(d[i][j], m[q][j] + d[i - 1][q]);
			d[i][j] = min(d[i][j], d[i - 1][j]);
			if (o >= d[i][j] && p[j] == 0) {
				e = j;
				o = d[i][j];
			}
		}
		p[e] = 1;
		q = e;
	}
	for (i = 0; i < n; i++)cout << i << ' ' << d[n - 1][i] << endl;
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#define INF 200001 
using namespace std;
int n;
int A[1000][1000];
int D[1000][1000];
  
int main(){
  scanf("%d",&n);
  int u,k,C,V;
   for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = INF;
   
  for(int i=0;i<n;i++){
      scanf("%d %d",&u,&k);    
      for(int j=0;j<k;j++){
    scanf("%d %d",&V,&C);
    D[u][V] = C;
    
      }    
  }
  for(int i=0;i<n;i++)D[i][i] = 0;
 
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= min(D[i][j],D[i][k] + D[k][j]);
 
  for(int i=0;i<n;i++)printf("%d %d\n",i,D[0][i]);
  
  
  return 0;
}

C++: //compiledef
#include <bits/stdc++.h>
#define rep(i, n) for(i=0;i<(n);i++)
#define per(i, n) for(i=(n);i>0;i--)
#define repx(i, n, x) for(i=(x);i<(n);i++)
#define xper(i, n, x) for(i=(n);i>(x);i--)
#define pback push_back

//c++def
using namespace std;
typedef long long int ll;
const ll MOD = 1e9+7;
const ll MOD2 = 998244353;
int n;
int w[10003][10003];
void daikustra(){
	int color[10003];
	int d[10003];
	int i;
	int v;
	int u= -1;
	rep(i, n){
		d[i] = 2e9;
		color[i] = 0;
	}
	d[0] = 0;
	color[0] = 1;
	while(999){
		int mincost = 2e9;
		rep(i, n){
			if(mincost>d[i] && color[i] !=2){
				u = i;
				mincost =d[i];
			}
		}
		if(mincost==2e9) break;
		color[u] = 2;
		for(v=0;v<n;v++){
			if(color[v] !=2&&w[u][v] != 2e9){
				if((d[u] + w[u][v])<d[v]){
					d[v] = d[u] + w[u][v];
					color[v] =1;
				}
			}
		}
	}
	rep(i, n){
		cout << i << " ";
		if(d[i] == 2e9)
			cout << -1;
		else
			cout<< d[i];
		cout <<endl;
	}
}

int main(){
	int i, j, k, l, u, v;
	cin >> n;
	rep(i, n)rep(j, n)w[i][j] = 2e9;
	rep(i, n){
		cin >> k >> l;
		rep(j, l){
			cin >> u >> v;
			w[k][u] = v;
		}
	}
	daikustra();
}

C++: #include<bits/stdc++.h>
using namespace std;
static const int MAX=100;
static const int INFTY=(1<<21);
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 <iostream>
#include <algorithm>
#include <cmath>
#include <cstdio>
using namespace std;
#define MAX 10000000

int b[110];

int solve(int a[110][110], int n){
	b[0] = 0;
	for(int i = 0;i < n;i++){
		for(int j = 1;j < n;j++){
			//if(j == 4)cout << b[4] << i << " " << endl;
			if(a[i][j] != -1)b[j] = min(b[j], a[i][j]+b[i]);
			//if(j == 4)cout << b[4] << i << " " << endl;
		}
	}
	//cout << endl;
	return 0;
}

int main(){
	int a[110][110], n;
	fill((int*)a, (int*)(a+110), -1);
	fill(b, b+110, MAX);
	cin >> n;
	for(int i = 0;i < n;i++){
		int u, k, c, d;
		cin >> u >> k;
		for(int j = 0;j < k;j++){
			cin >> c >> d;
			a[u][c] = a[c][u] = d;
		}
	}
	for(int i = 0;i < 2*n;i++)solve(a, n);
	for(int i = 0;i < n;i++){
		cout << i << " " << b[i] << endl;
	}
	
	return 0;
}
/*
5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3
*/