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>

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, M[MAX][MAX];

void dijkstra(){
  int minv;
  int d[MAX], color[MAX];
	
  for(int i=0;i < n;++i){
    d[i] = INFTY;
    color[i] = WHITE;
  }
	
  d[0] = 0;
  color[0] = GRAY;
  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 << " ";
    if(d[i] == INFTY) cout << -1 << endl;
    else cout << d[i] << endl;
  }
}

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>
using namespace std;
#define N 100
static const int infinity =(1<<21);
static const int white =0;
static const int gray = 1;
static const int black =2;

int n,M[N][N];

void dijkstra(){
    int min,u;
    int color[N],d[N];
    
    for(int i=0;i<n;i++){
        color[i]=white;
        d[i]=infinity;
    }
    
    d[0]=0;
    
    while(1){
        min=infinity;
        int u=-1;
        for(int i=0;i<n;i++){
            if(color[i]!=black&&d[i]<min){
                min=d[i];
                u=i;
            }
        }
        if(min==infinity)break;
        
        color[u]=black;
        
        for(int v=0;v<n;v++){
            if(color[v]!=black&&M[u][v]!=infinity){
                if(d[u]+M[u][v]<d[v]){
                    d[v]=d[u]+M[u][v];
                    color[v]=gray;
                }
            }
        }
    }
    for(int i=0;i<n;i++)cout<<i<<" "<<d[i]<<endl;
}

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

C++: #include <iostream>
#include <vector>
#include <queue>
#include <functional>
#include <string.h>

using namespace std;
static const int INF = 1e9;
typedef pair<int, int> P;
struct edge
{
	int to;
	int cost;
};

int d[101];
vector<edge> G[101];

void solve()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int to, cost;
			cin >> to >> cost;
			edge e1, e2;
			e1.to = to;
			e1.cost = cost;
			e2.to = u;
			e2.cost = cost;
			G[u].push_back(e1);
			G[to].push_back(e2);
		}
	}
	for (int i = 0; i < 101; ++i)
	{
		d[i] = INF;
	}
	d[0] = 0;
	priority_queue<P, vector<P>, greater<P> > pque;
	pque.push(P(0, 0));
	while (!pque.empty())
	{
		P p = pque.top();
		pque.pop();
		int v = p.second;
		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;
				pque.push(P(d[e.to], e.to));
			}
		}
	}
	for (int i = 0; i < n; ++i)
	{
		cout << i << " " << d[i] << endl;
	}
}

int main()
{
	solve();
	return(0);
}

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, M[MAX][MAX];

void dijkstra() {
  int minv;
  int d[MAX], color[MAX];

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

  d[0] = 0;
  color[0] = GRAY;
  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]) << endl;
  }
}

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;
}