Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include<iostream>
using namespace std;
#define S 100
#define INF 1000000
#define WHITE 0;
#define GRAY 1;
#define BLACK 2

int n,a[S][S];

void dijkstra(){
    int minv;
    int d[S],cnd[S];
    int i,v;
    for(i=0;i<n;i++){
        d[i]=INF;
        cnd[i]=WHITE;
    }

    d[0]=0;
    cnd[0]=GRAY;

    while(1){
        minv=INF;
        int u=-1;
        for(i=0;i<n;i++){
            if(minv>d[i]&&cnd[i]!=BLACK){
                u=i;
                minv=d[i];
            }
        }
        if(u==-1)break;
        cnd[u]=BLACK;
        for(int v=0;v<n;v++){
            if(cnd[v]!=BLACK && a[u][v]!=INF){
                if(d[v]>d[u]+a[u][v]){
                    d[v]=d[u]+a[u][v];
                    cnd[v]=GRAY;
                }
            }
        }
    }

    for(int i=0;i<n;i++){
            cout<<i<<" "<<(d[i]==INF?-1:d[i])<<endl;
    }
}

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

C++: #include<cstdio>
#include<climits>
#include<cstring>
#define INF 1<<25
using namespace std;
typedef long ull;
 
int main(){
  int n;
  int A[1000][1000];
  ull D[1000][1000];
  scanf("%d",&n);
  int u,k,C,V;
  
  for(int i=0;i<=n;i++){
    for(int j=0;j<=n;j++)D[i][j] = INF;
  }
  
  for(int i=0;i<n;i++){
    scanf("%d %d",&u,&k);    
    for(int j=0;j<k;j++){
      scanf("%d %d",&V,&C);
      D[u][V] = C;
      D[V][u] = C;
    }    
  }
  
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++){
    cout << i << " " << D[0][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 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][v]+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++: #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++: #include<bits/stdc++.h>

typedef long long ll;

using namespace std;

int n;
int G[10010][10010];
int minlen[10010];
bool vis[10010];


void dijkstra(int p){
	memset(minlen,-1,sizeof(minlen));
	memset(vis,0,sizeof(0));
	
	minlen[p] = 0;
	
	while (1){
		int minp = -1;
		int minn = 1<<30;
	
		for(int i = 0 ; i<n ; i++){
			if(!vis[i] && minlen[i]!=-1 && minn>minlen[i]){
				minp = i;
				minn = minlen[i];
			}
		}
		if(minp == -1) break;
		
		vis[minp] = 1;
		for(int j = 0 ; j<n ; j++){
			if(!vis[j] && G[minp][j]!=1<<30){
				if(minlen[j] == -1){
					minlen[j] = minlen[minp]+G[minp][j];
				}
				else if( minlen[j] > minlen[minp]+G[minp][j]){
					minlen[j] = minlen[minp]+G[minp][j];
				}
			}
		}
	}
}

int main(){
	ios::sync_with_stdio(false);
	cin>>n;
	for(int i = 0 ; i<n ; i++)
		for(int j = 0 ; j<n ; j++)
			G[i][j] = 1<<30;
	
	for(int t = 0 ; t<n ; t++){
		int u,k;
		cin>>u>>k;
		for(int i = 0 ; i<k ; i++){
			int to,weight;
			cin>>to>>weight;
			G[u][to] = weight;
		}
	}

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

C++: #include <iostream>
using namespace std;
static const int MAX=101;
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 i=0;i<n;i++){
            if(color[i]!=BLACK && M[u][i]!=INFTY){
                if(d[i]>M[u][i]+d[u]){
                    d[i]=M[u][i]+d[u];
                    color[i]=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;
        }
    }
    
    for(int i=0;i<n;i++){
        int x,y;cin >> x >> y;
        for(int j=0;j<y;j++){
            int z;cin >> z;
            cin >> M[x][z];
        }
    }
    
    dijkstra();
    
    return 0;
}