Go: package main

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

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := make(map[int]int)
	q[0] = 0
	visited := make(map[int]struct{})
	out := make([]int, n)

	for len(q) > 0 {
		u := top(q)
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			if d, ok := q[uu]; !ok || d > q[u]+c {
				q[uu] = q[u] + c
			}
		}

		out[u] = q[u]
		delete(q, u)
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

func top(q map[int]int) int {
	minu := -1
	min := -1
	for u, d := range q {
		if min < 0 || d < min {
			minu = u
			min = d
		}
	}

	return minu
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#define INF 2000 
using namespace std;
int n;
int A[1000][1000];
int d[1000];
bool used[1000];
int D[1000][1000];
 
void Init(int f){
  for(int i=0;i<f;i++){
    for(int j=0;j<f;j++)D[i][j] = INF;
  }
 
}
 
int main(){
  scanf("%d",&n);
  int u,k,C,V;
  Init(n);
  
  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++){
    printf("%d %d\n",i,D[0][i]);
  }
 
  return 0;
}

C++: #include <iostream>
using namespace std;
#define MAX 100
#define INFTY 10000001
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define DEFLT 0 // 初期値

int M[MAX][MAX], d[MAX];

void dijkstra(int n){
  int mincost, u, color[n], p[n];
  for(int i=0; i<n; i++){
    color[i] = WHITE;
    d[i] = INFTY;
  }

  d[DEFLT] = 0;
  p[DEFLT] = -1;

  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 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(void){
  int n, u, k, v, c;
  cin >> n;

  for(u=0; u<MAX; u++){
    for(v=0; v<MAX; v++){
      M[u][v] = 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(n);

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

C++: #include<bits/stdc++.h>
#include<string>
#include<cctype>
#include<cmath>
#include<queue>
#include<stack> 
#define rep(i,n) for(int i=0;i<(n);i++)
using namespace std;
const int MAX_V=105;
int INF = 1000000000;
struct edge{int to,cost;};
typedef pair <int,int> P;

int V;
vector <edge> G[MAX_V];
int d[MAX_V];

void dijkstra(int s){
  priority_queue<P,vector<P>,greater<P> > que;
  fill(d,d+V,INF);
  d[s]=0;
  que.push(P(0,s));
  
  while(!que.empty()){
    P p = que.top(); que.pop();
    int v= p.second;
    if(d[v]<p.first)continue;
    for(int i=0 ;i<G[v].size();i++){
      edge e =G[v][i];
      if(d[e.to]>d[v]+e.cost){
        d[e.to] = d[v] + e.cost;
        que.push(P(d[e.to],e.to));
      }
    }
  }
} 
  
int main(){
  int n;
  cin >> n; V=n;
  rep(i,n){
    int u,k;
    cin >> u >> k;
    rep(j,k){
      int to,cost;
      cin >> to >> cost;
      G[u].push_back(edge{to,cost});
    }
  }     

  dijkstra(0);
  rep(i,n){
    cout << i << ' ' << d[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <queue>
#define INF 1000000000
using namespace std;

struct edge{ int to,cost; };
typedef pair<int,int> P;

int main(){
	int n;
	vector<edge> es[100];
	priority_queue<P,vector<P>,greater<P> > que;
	int d[100];
	cin >> n;
	for(int i = 0;i < n;i++){
		int now,m;
		cin >> now >> m;
		for(int j = 0;j < m;j++){
			int a,b;
			cin >> a >> b;
			es[now].push_back({a,b});
		}
		d[i] = INF;
	}
	d[0] = 0;
	que.push(make_pair(0,0));
	while(!que.empty()){
		P p = que.top();
		que.pop();
		int v = p.second;
		if(d[v] < p.first) continue;
		for(int i = 0;i < es[v].size();i++){
			edge e = es[v][i];
			if(d[e.to] > d[v] + e.cost){
				d[e.to] = d[v] + e.cost;
				que.push(make_pair(d[e.to],e.to));
			}
		}
	}
	for(int i = 0;i < n;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 n, M[MAX][MAX];

int 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++: //
//  main.cpp
//  minnimum_spanning_tree
//
//  Created by ???????????? on 2017/10/23.
//  Copyright ?? 2017 ????????????. All rights reserved.
//

#include <iostream>
#include <stdio.h>

#define n_max 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INFTY 1<<21

using namespace std;

int n, M[n_max][n_max], color[n_max], d[n_max], p[n_max];

void init(){
    int i, j, id, num, node;
    scanf("%d", &n);
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            M[i][j] = INFTY;
        }
    }
    
    
    for(i = 0; i < n; i++){
        scanf("%d %d", &id, &num);
        for(j = 0; j < num; j++){
            scanf("%d", &node);
            scanf("%d", &M[id][node]);
        }
        color[i] = WHITE;
        d[i] = INFTY;
    }
}

void dijkstra(){
    //initializing
    d[0] = 0;
    p[0] = -1;
    
    int u;
    while(true){
        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] = M[u][v] + d[u];
                    p[v] = u;
                    color[v] = GRAY;
                }
            }
        }
    }
    for(int i = 0; i < n; i++){
        cout<<i<<" "<<d[i]<<endl;
    }
}

int main(int argc, const char * argv[]) {
    init();
    dijkstra();
    //    std::cout << "Hello, World!\n";
    return 0;
}