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 <bits/stdc++.h>
/*
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cstring>
#include <complex>
#include <stack>
#include <queue>
#include <unordered_map>
#include <map>
*/

#define INF 10e9
#define rep(i, a) for (int i = 0; i < (a); i++)
using namespace std;


int main() {
   long long int n;
   cin >> n;

   vector<pair<long long int, long long int> > graph[n];
   long long int u, k, v, c;

   long long int i, j;
   for(i = 0; i < n; i++){
       cin >> u >> k;
       for(j = 0; j < k; j++){
           cin >> v >> c;
           pair<long long int, long long int> p = make_pair(v, c);
           graph[u].push_back(p);
       }
   }

   int used[n];
   long long int d[n];

   for(i = 0; i < n; i++){
       used[i] = 0;
       if(i == 0){
           d[i] = 0;
       }else{
           d[i] = INF;
       }
   }

   for(i = 0; i < n; i++){
       long long int id;
       for(j = 0; j < n; j++){
           if(used[j] != 1){
               id = j;
               break;
           }
       }
       for(j = 0; j < n; j++){
           if(used[j] != 1 && d[id]>d[j]){
               id = j;
           }
       }
       used[id] = 1;
       for(j = 0; j < graph[id].size(); j++){
           d[graph[id][j].first] = min(d[graph[id][j].first], d[id] + graph[id][j].second);
       }
   }

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

C++: # include <iostream>
# include <memory.h>
using namespace std;
static const int MAX = 100;
static const int INF = 0x7fffffff;
int n,a[MAX][MAX];
void dijkstra()
{
	int minv;
	int d[MAX];
	bool vis[MAX];
	for(int i = 0;i < n;i++)
	{
		d[i] = INF;
		vis[i] = false;
	}
	d[0] = 0;
	while(true)
	{
		minv = INF;
		int u = -1;
		for(int i = 0;i < n;i++)
		{
			if(!vis[i] && minv > d[i])
			{
				u = i;
				minv = d[i];
			}
		}
		if(u == -1) break;
		vis[u] = 1;
		for(int v = 0;v < n;v++) if(!vis[v] && a[u][v] != INF) d[v] = min(d[v],d[u]+a[u][v]);
	}
	for(int i = 0;i < n;i++) printf("%d %d\n",i,(d[i] == INF)?-1:d[i]);
} 
int main(void)
{
	int u,v,k,dis;
	scanf("%d",&n);
	for(int i = 0;i < n;i++) for(int j = 0;j < n;j++) a[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,&dis);
			a[u][v] = dis;
		}
	}
	dijkstra();
	return 0;
}

C++: #include<iostream>
using namespace std;
static const int MAX=100;
static const int INFTY=2000000000;
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int n,M[MAX+1][MAX+1];
void dijkstra(){
    int minv;
    int d[MAX+1],color[MAX+1];
    for(int i=1;i<=n;i++){
        d[i]=INFTY;
        color[i]=WHITE;
    }
    d[0]=0;
    while(1){
        minv=INFTY;
        int u=-1;
        for(int 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(int v=0;v<n;v++){
            if(color[v]!=BLACK&&M[u][v]!=INFTY){
                if(d[v]>d[u]+M[u][v]){
                    d[v]=d[u]+M[u][v];
                    color[v]=GRAY;
                }
            }
        }
    }
    for(int i=0;i<n;i++)
        cout<<i<<" "<<(d[i]==INFTY?-1:d[i])<<"\n";
}
int main(){
    cin>>n;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++)
            M[i][j]=INFTY;
    }
    int k,c,u,v;
    for(int i=0;i<n;i++){
        cin>>u>>k;
        for(int j=0;j<k;j++){
            cin>>v>>c;
            M[u][v]=c;
        }
    }
    dijkstra();
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <utility>
#define INF 10000000
using namespace std;



int main(){
  int n;
  cin >> n;
  vector<vector<int>> graph(n, vector<int>(n, INF));
  for (int i=0;i<n;i++)
    graph[i][i] = 0;
  for (int i=0;i<n;++i){
    int id,k;
    cin >> id >> k;
    for(int j=0;j<k;++j){
      int to, c;
      cin >> to >> c;
      graph[id][to] = c;
    }
  }
  for (int i=0;i<n; ++i){
    for (int j=0;j<n;j++){
      for (int k=0;k<n;k++){
        graph[j][k] = min(graph[j][k], graph[j][i] + graph[i][k]);
      }
    }
  }

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

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int MOD = 1000000007;

struct edge {int to, cost; };
using P = pair<int , int>;
int V;
vector <edge> G[100010];
int d[100010];

void dijkstrra(int s){
    priority_queue <P, vector<P>, greater<P> > que;
    fill(d, d + V, 1000000000);
    d[s] = 0;
    que.push(P(0 , s));
    
    while(!que.empty()){
        P p = que.top(); que.pop();
        int v = p.second;
        if(d[v] < p.first)  continue;
        for(int i = 0; i < G[v].size(); i++){
            edge e = G[v][i];
            if(d[e.to] > d[v] + e.cost){
                d[e.to] = d[v] + e.cost;
                que.push(P(d[e.to], e.to));
            }
        }
    }
}

int main(){
    int n;
    cin >> n;
    V = n;
    for(int i = 0; i < n; i++){
        int u, k;
        cin >> u >> k;
        int v,c;
        for(int i = 0; i < k; i++){
            cin >> v >> c;
            G[u].push_back(edge{v, c});
        }
    }
    dijkstrra(0);
    for(int i = 0; i < n; i++)
        cout << i << " " << d[i] << endl;
    return 0;
}