Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include <iostream>

using namespace std;
int M[100][100]; //?????\??????
int n; //n?????¶?????°
static const int WHITE=0; //?????????????????°
static const int GRAY=1; //??°??????????????°
static const int BLACK=2; //????????????????????\
static const int INFTY=(1<<21);  //??£??¨??£??????
void dijkstra()
{
    int color[100];  //????????¶???????¢????
    int d[100]; //????????¶????????????????°?????????????????????????T??????????????????
    for(int i=0;i<n;i++)
       {
          d[i]=INFTY;  //???????§??????¶?????????????????????????????????????§?????????£??????
          color[i]=WHITE;
       }
    d[0]=0; //???????????????????????????d???0
    while(1)
    {
        int r=-1;int minv=INFTY;
        //?????°??????????°????????????\??°??????T???
        for(int i=0;i<n;i++)
        {
            if(color[i]!=BLACK&&d[i]<minv)
            {
                r=i;minv=d[i];
            }
        }
        if(r==-1) break; //?????????????????¶???-1????????´????????????????????????????????????????????????
        color[r]=BLACK; //?????????????°?????????\??????T??????????°±???????????¶??????BLACK
        //?????¶??????T????????°??????????????\?????´??°??????????????¶???
        //??´??°??¶????????¶??????????????°????????£??????????????\????????¶???????????´??°??????
        for(int i=0;i<n;i++)
        {
            if(color[i]!=BLACK&&M[r][i]!=INFTY) //?????????????????\?????????????????????
            {
                if(d[i]>M[r][i]+d[r]) //?????????????????????
                {
                    d[i]=M[r][i]+d[r];
                    color[i]=GRAY;
                }
            }
        }
    }
    for(int i=0;i<n;i++)
    {
        cout<<i<<" "<<(d[i]==INFTY?-1:d[i])<<endl;
    }
}
int main()
{
    while(cin>>n)
    {
        //????§?????????\??????
        for(int i=0;i<n;i++)
            for(int j=0;j<n;j++)
                M[i][j]=INFTY;
        int u,k,v,c;
        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<queue>
#define INF 100000000
using namespace std;
int main(){
  int n;cin>>n;
  int u,k,v,c;
  int mp[101][101],d[101];
  for(int i=0;i<=100;i++){
    d[i]=INF;
    for(int j=0;j<=100;j++)mp[i][j]=INF;
  }
    while(u!=n-1){
    cin>>u>>k;
    for(int i=0;i<k;i++){
      cin>>v>>c;
      if(mp[u][v]>c)mp[u][v]=c;
    }
  }
    d[0]=0;
    queue<int>p;
    p.push(0);
    int mn,s=0,cnt=n;
    while(cnt&&!p.empty()){
      s=p.back();
      mn=INF;
      for(int i=0;i<n;i++){
	if(d[i]>=d[s]+mp[s][i]){
	  d[i]=d[s]+mp[s][i];
	  if(mn>d[i])mn=d[i],k=i;
	}
      }
      if(mn!=INF)cnt--,p.push(k);
      else p.pop();
    }
    for(int i=0;i<n;i++)cout<<i<<" "<<d[i]<<endl;
    
  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#define Lens 101
#define Inf 1<<22

using namespace std;
int N;
int w[Lens][Lens],p[Lens],d[Lens];
char c[Lens];

void dijkstra()
{
	d[0] = 0;
	while (true)
	{
		int u = -1;
		int minv = Inf;
		for (int i = 0; i < N; i++)
		{
			if (c[i] == 'w'&&minv > d[i])
			{
				minv = d[i];
				u = i;
			}
		}
		if (u == -1) break;
		c[u] = 'b';
		for (int v = 0; v < N; v++)
		{
			if (c[v] == 'w'&&w[u][v] != Inf)
				d[v] = min(d[v], w[u][v]+d[u]);
		}
	}
}

int main()
{
	cin >> N;
	for (int i = 0; i < N; i++)
	{
		c[i] = 'w';
		d[i] = Inf;
		p[i] = -1;
		int u,n;
		cin >> u >> n;
		for (int j = 0; j < n; j++)
		{
			int v, tw;
			cin >> v >> tw;
			w[u][v] = tw;
		}
	}
	for(int i=0;i<N;i++)
		for (int j = 0; j < N; j++)
		{
			if (w[i][j] == 0)
				w[i][j] = Inf;
		}
	dijkstra();
	for (int i = 0; i < N; i++)
		cout << i <<' '<< d[i] << endl;
	return 0;
}

C++: //
//  ALDS_12_B.cpp
//  
//
//  Created by 杵鞭俊 on 2018/07/24.
//

#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 << " "<<(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;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <stdio.h>
#include <cstring>
#define maxn 101
#define INF 0x3f3f3f3f
using namespace std;

int m[maxn][maxn] = {}, d[maxn] = {}, color[maxn] = {};
int n;

void Dijkstra()
{
	for (int i = 1; i < n; i++)
		d[i] = INF;
	d[0] = 0;
	while (true)
	{
		int mincost = INF,u;
		for(int i=0;i<n;i++)
			if (d[i] < mincost&&color[i]==0)
			{
				mincost = d[i];
				u = i;
			}
		if (mincost == INF)break;
		color[u] = 1;
		for (int i = 0; i < n; i++)
			if (color[i] == 0 && m[u][i] != -1)
				if (d[i] > d[u] + m[u][i])
					d[i] = d[u] + m[u][i];
	}
}
int main()
{
	scanf("%d", &n);
	memset(m, -1, sizeof(m));
	for (int i = 0; i < n; i++)
	{
		int u, k;
		scanf("%d %d", &u, &k);
		for (int i = 0; i < k;i++)
		{
			int v, c;
			scanf("%d%d", &v, &c);
			m[u][v] = c;
		}
	}
	Dijkstra();
	for (int i = 0; i < n; i++)
	{
		printf("%d %d\n", i, d[i]);
	}
	return 0;
}