Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const (
	INFTY = 1 << 21
	NIL   = -1
)

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph [][]int

func (g *Graph) dikstra(n int) string {
	var (
		u, minv = 0, 0
	)

	d := make([]int, n)
	color := make([]int, n)

	for i := 0; i < n; i++ {
		d[i] = INFTY
		color[i] = WHITE
	}
	d[0] = 0
	color[0] = GRAY

	for {
		minv = INFTY
		u = -1
		for 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 v := 0; v < n; v++ {
			if color[v] != BLACK && (*g)[u][v] != INFTY {
				if d[v] > d[u]+(*g)[u][v] {
					d[v] = d[u] + (*g)[u][v]
					color[v] = GRAY
				}
			}
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d ", i))
		if d[i] == INFTY {
			out.WriteString(fmt.Sprintf("%d\n", -1))
			continue
		}
		out.WriteString(fmt.Sprintf("%d\n", d[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	g := make(Graph, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for j := 0; j < n; j++ {
			g[i][j] = INFTY
		}
	}

	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())

		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			sc.Scan()
			c, _ := strconv.Atoi(sc.Text())

			g[u][v] = c
		}
	}

	return g.dikstra(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
const int MAX=105;
const int INF= 1<<30;
int M[MAX][MAX],n,d[MAX],p[MAX],vis[MAX];
void init(){
	for(int i=0;i<n;i++){
		d[i]=INF;
		p[i]=-1;
		vis[i]=0;
	}
	d[0]=0;
}
void dijkstra(){
	init();
	while (true){
		int u=-1;
		int minCost=INF;
		for(int i=0;i<n;i++){
			if(!vis[i] && d[i]<minCost){
				u=i;
				minCost=d[i];
			}
		}
		if(u==-1)break;
		vis[u]=1;
		for(int i=0;i<n;i++){
			if(!vis[i] && M[u][i]!=-1 &&M[u][i]+d[u]<d[i]){
				d[i]=M[u][i]+d[u];
				p[i]=u;
			}
		}
	}
}
int main(){
	cin>>n;
	memset(M,-1,sizeof(M));
	for(int i=0;i<n;i++){
		int u,k,v,c;
		cin>>u>>k;
		for(int j=0;j<k;j++){
			cin>>v>>c;
			M[u][v]=c;
		}
	}
	dijkstra();
	for(int i=0;i<n;i++){
		printf("%d %d\n",i,d[i]);
	}
	return 0;
}

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;
}