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, INFTY = (1 << 21), WHITE = 0, GRAY = 1, BLACK = 2;

int N, M[MAX][MAX];
void dijkstra() {
	int minv;
	int D[MAX], C[MAX];

	for (int i = 0; i < N; i++) {
		D[i] = INFTY;
		C[i] = WHITE;
	}

	D[0] = 0;
	C[0] = GRAY;
	while (true) {
		minv = INFTY;
		int u = -1;
		for (int i = 0; i < N; i++) {
			if (minv > D[i] && C[i] != BLACK) {
				u = i;
				minv = D[i];
			}
		}
		if (u == -1) break;
		C[u] = BLACK;
		for (int v = 0; v < N; v++) {
			if (C[v] != BLACK && M[u][v] != INFTY) {
				if (D[v] > D[u] + M[u][v]) {
					D[v] = D[u] + M[u][v];
					C[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();
}

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];
		}
	}

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

	return 0;
}

C++: #include <iostream>
#define N 100
#define INFINITY 200000000
using namespace std;
int n,k,u,v,c,M[N][N],d[N],p[N],mincost,i,j;
string color[N];
void dijkstra(void);
int main(){
  cin >> n;
  for(i=0;i<n;i++){
    for(j=0;j<n;j++){
      M[i][j]=-1;
    }
  }
  for(i=0;i<n;i++){
    cin >> u;
    cin >> k;
    for(j=0;j<k;j++){
      cin >> v >> c;
      M[u][v]=c;
    }
  }
  dijkstra();
  return 0;
}
void dijkstra(){
  for(i=0;i<n;i++) color[i]="WHITE",d[i]=INFINITY;
  d[0]=0;
  p[0]=-1;
  while(1){
    mincost=INFINITY;
    for(i=0;i<n;i++){
      if(color[i]!="BLACK"&&d[i]<mincost){
	mincost=d[i];
	u=i;
      }
    }
    if(mincost==INFINITY) break;
    color[u]="BLACK";
    for(i=0;i<n;i++){
      if(color[i]!="BLACK"&&M[u][i]!=-1){
	if(d[u]+M[u][i]<d[i]){
	  d[i]=d[u]+M[u][i];
	  p[i]=u;
	  color[i]="GLAY";
	}
      }
    }
  }
  for(i=0;i<n;i++) cout << i << ' ' << d[i] << endl;
}

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];
int prim(){
    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;
        }
    }
    prim();
    return 0;
}