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++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdlib>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>

using namespace std;

static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int NIL = -1;
static const int MAX = 100;
static const int INFTY = 10000000;


int colors[MAX] = { WHITE };	//各頂点の訪問状態
int graph[MAX][MAX] = { INFTY };
int d[MAX] = { INFTY };		//原点からの各頂点の距離
int p[MAX] = { NIL };		//親頂点

void dijkstra(int n) {

    d[0] = 0;
    colors[0] = WHITE;

    while (true) {

	int mincost = INFTY;
	int u;

	for (int i = 0; i < n; i++) {
	    //まだコストが確定しておらず、かつ現時点で仮コストが出ているもの
	    if (colors[i] != BLACK&&d[i] != INFTY) {

		//より小さいコストの原点からの距離があったら
		if (d[i] < mincost) {
		    mincost = d[i];
		    u = i;
		}
	    }
	}

	if (mincost == INFTY) {
	    break;
	}

	colors[u] = BLACK;

	//確定した頂点uからの近隣探索
	for (int i = 0; i < n; i++) {
	    
	    //まだ確定しておらずvから辺があれば
	    if (colors[i] != BLACK&&graph[u][i] != INFTY) {


		//現時点でiに行くコストより
		//頂点uを経由した方がコストが小さかったら
		if (d[u]+graph[u][i] < d[i]) {
		    d[i] = d[u] + graph[u][i];
		    p[i] = u;
		}

	    }

	}

    }
}

int main() {

    //cin.tie(0);
    //ios::sync_with_stdio(false);
    
    int n; scanf("%d", &n);
    int u; //頂点
    int k; //vからの辺の数
    int v; //uにつながる頂点v
    int c; //コスト

    //グラフ初期化
    for (int i = 0; i < n; i++) {
	for (int j = 0; j < n; j++) {
	    graph[i][j] = INFTY;
	}
    }
    
    //距離d初期化
    for(int i = 0; i < n; i++) {
	d[i] = INFTY;
    }

    //グラフ読み込み
    for (int i = 0; i < n; i++) {
	scanf("%d", &u);
	scanf("%d", &k);
	for (int j = 0; j < k; j++) {
	    scanf("%d", &v);
	    scanf("%d", &c);
	    graph[u][v] = c;
	}
    }


    //ダイクストラ法
    dijkstra(n);

    //表示
    for (int i = 0; i < n; i++) {
	printf("%d %d\n", i, d[i]);
    }

    return 0;

}

C++: #include <iostream>
#include <algorithm>
using namespace std;

#define MAX_VERTEX 100
#define INF 1000000

int cost[MAX_VERTEX][MAX_VERTEX];
int d[MAX_VERTEX];
bool used[MAX_VERTEX];

int main() {
  int vertex_num;
  cin >> vertex_num;

  for(int i = 0; i < vertex_num; i++) {
    d[i] = INF;
    used[i] = false;
    for(int j = 0; j < vertex_num; j++) {
      cost[i][j] = INF;
    }
  }

  for (int i = 0; i < vertex_num; i++) {
    int vertex, out;
    cin >> vertex >> out;
    for(int j = 0; j < out; j++) {
      int to, c;
      cin >> to >> c;
      cost[vertex][to] = c;
    }
  }

  d[0] = 0;
  while(true) {
    int vertex = -1;
    for(int u = 0; u < vertex_num; u++) {
      if(!used[u] && (vertex == -1 || d[u] < d[vertex])) {
        vertex = u;
      }
    }

    if (vertex == -1) break;

    used[vertex] = true;

    for(int u = 0; u < vertex_num; u++) {
      d[u] = min(d[u], d[vertex] + cost[vertex][u]);
    }
  }

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

  return 0;
}

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 M[MAX][MAX], color[MAX], d[MAX], p[MAX];

int n;

void dijkstra(int s){
    int u = s;
    for(int u = 0; u < n; u++){
        color[u] = WHITE;
        d[u] = INFTY;
    }
    d[s] = 0;
    p[s] = -1;

    while(1){
        int 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 v = 0; v < n; v++){
            if(color[v] != BLACK && M[u][v] != INFTY){
                if(d[u] + M[u][v] < d[v]){
                    d[v] = d[u] + M[u][v];
                    p[v] = u;
                    color[v] = GRAY;
                }
            }
        }
    }
}
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] = INFTY;
        }
    }

    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(0);

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

    return 0;
}