Go: package main

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

const (
	white int = iota
	gray
	black
)

type node struct {
	id     int
	parent int
	edge   []int
	weight []int
	color  int
}

type graph struct {
	nodes    []node
	distance []int
}

var infty = 1 << 32
var null = -1

func constructgraph() *graph {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n := nextInt(sc)

	g := &graph{make([]node, n), make([]int, n)}

	for i := 0; i < n; i++ {
		id := nextInt(sc)
		edges := nextInt(sc)
		n := node{}
		n.id = id
		n.edge = make([]int, edges)
		n.weight = make([]int, edges)
		n.color = white
		for j := 0; j < edges; j++ {
			to := nextInt(sc)
			w := nextInt(sc)
			n.edge[j] = to
			n.weight[j] = w
		}
		g.nodes[id] = n
	}
	return g
}

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func (g *graph) preparedijkstra(s int) {
	for i := 0; i < len(g.nodes); i++ {
		g.nodes[i].color = white
		g.nodes[i].parent = null
		g.distance[i] = infty
	}
	g.distance[s] = 0
}

func (g *graph) dijkstra(s int) []int {
	g.preparedijkstra(s)

	for {
		var u int
		mincost := infty
		for i, d := range g.distance {
			if g.nodes[i].color != black && mincost > d {
				mincost = d
				u = i
			}
		}

		if mincost == infty {
			break
		}

		g.nodes[u].color = black

		for i, e := range g.nodes[u].edge {
			if g.nodes[e].color != black {
				if g.distance[e] > g.distance[u]+g.nodes[u].weight[i] {
					g.distance[e] = g.distance[u] + g.nodes[u].weight[i]
					g.nodes[e].parent = u
					g.nodes[e].color = gray
				}
			}
		}
	}
	return g.distance
}

func printShortestPath(d []int) {
	for i, v := range d {
		fmt.Printf("%d %d\n", i, v)
	}
}

func main() {
	g := constructgraph()
	d := g.dijkstra(0)
	printShortestPath(d)
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxx=110;
const int infinity=(1<<21);

int A[maxx][maxx];
int d[maxx];
bool flag[maxx];

int main (){
	int n,a,b,c,minv,mini;
	cin>>n;
	for(int i=0;i<maxx;i++){
		flag[i]=false;
		d[i]=infinity;
		for(int j=0;j<maxx;j++){
			A[i][j]=infinity;
		}
	}
	for(int i=0;i<n;i++){
		cin>>a>>b;
		for(int j=0;j<b;j++){
			cin>>c>>A[a][c];
		}
	}
	
	d[0]=0;
	while(1){
		minv=infinity,mini=-1;
		for(int i=0;i<n;i++){
			if(flag[i]==false && d[i]<minv){
				minv=d[i];
				mini=i;
			}
		}
		if(mini==-1 || minv==infinity) break;
		flag[mini]=true;
		for(int i =0;i<n;i++){
			if(A[mini][i]!=infinity && flag[i]==false && d[mini]+A[mini][i]<d[i]){
					d[i]=d[mini]+A[mini][i];
			}
		}
		
	}
	cout<<n<<endl;
	int nn=n;
	for(int i=0;i<nn;i++) cout<<i<<" "<<d[i]<<endl;
	
	return 0;

}

C++: #include <iostream>

using namespace std;

int n;
int a[124][124] = {{}};
static const int INFTY = 1000000;

void dijkstra(){
  int flag[124] = {};
  int d[124] = {};
  int p[124] = {};
  int minv;
  int u;

  for (int i = 0;i < n;i++){
    d[i] = INFTY;
    p[i] = -1;
  }
  d[0] = 0;
  while(1){
    minv = INFTY;
    u = -1;

    for(int i = 0;i < n;i++){
      if(flag[i] == 0 && minv > d[i]){
        minv = d[i];
        u = i;
      }
    }
  //  cout << "u = " << u << endl;
  //  cout << "minv = " << minv << endl;
    if(u == -1) break;
    flag[u] = 1;

    for(int i = 0;i < n;i++){
      if(d[i] > d[u] + a[u][i] && a[u][i] != INFTY && flag[i] == 0){
        d[i] = d[u] + a[u][i];
        p[i] = u;
      }
    }
  }

  for(int i = 0;i < n;i++){
    if(d[i] != -1){
      cout << i <<  " " << d[i] << endl;
    }
    else cout << i << " " << -1 << endl;
  }
}



int main(){

  cin >> n;

  for (int i = 0 ;i < n;i++){
    for(int j = 0;j < n;j++){
      a[i][j] = INFTY;
    }
  }


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

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#define INF 200001 
using namespace std;
int n;
int A[1000][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;
   
      }    
  }
  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>
#include <queue>
#include <utility>
#include <vector>
#include <functional>
using namespace std;
int cost[100][100];
const int INF = 10000000;
int dijkstra(int n,int s,int g){
	typedef pair<int,int> P;
	int mincost;
	{priority_queue<P,vector<P>,greater<P> > pq;
	P p,tp;
	for(int i = 0;i < n;++i){
		p.first = cost[s][i];
		p.second = i;
		if(i == s) p.first = 0;
		pq.push(p);
	}
	while(!pq.empty()){
		p = pq.top();
		pq.pop();
		if(p.second == g) break;
		for(int i = 0;i < n;++i){
			if(cost[p.second][i] != INF && p.first != INF){
				tp.first = p.first + cost[p.second][i];
				tp.second = i;
				pq.push(tp);
			}
		}
	}
	mincost = p.first;
	}
	return mincost;
}
int main(){
	int n,m,a,b,c;
	cin >> n;
	for(int i = 0;i < 100;++i){
		for(int j = 0;j < 100;++j){
			cost[i][j] = INF;
		}
	}
	for(int i = 0;i < n;++i){
		cin >> a >> m;
		for(int j = 0;j < m;++j){
			cin >> b >> c;
			cost[a][b] = c;
		}
	}
	for(int i = 0;i < n;++i){
		cout << i << " " << dijkstra(n,0,i) << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<vector>

struct Edge {
	int to, weight;
};

int main()
{
	int n, u, k, v, c, distance[100]{}, upd_num = 1;
	bool must_update[100]{ 1 };
	std::vector<Edge> dest[100];

	std::cin >> n;
	for (int i = 0; i < n; ++i)
	{
		std::cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			std::cin >> v >> c;
			dest[u].push_back({ v, c });
		}
		if (i)
			distance[i] = 2000000000;
	}

	while (upd_num)
		for (int i = 0; i < n && upd_num; i++)
		{
			if (!must_update[i]) continue;

			must_update[i] = false;
			upd_num--;
			for (auto e : dest[i])
			{
				int tmp = distance[i] + e.weight;
				if (tmp < distance[e.to])
				{
					distance[e.to] = tmp;
					if (!must_update[e.to])
					{
						must_update[e.to] = true;
						upd_num++;
					}
				}
			}
		}

	for (int i = 0; i < n; i++)
	{
		std::cout << i << " " << distance[i] << std::endl;
	}

	return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#define MAX_V 100
#define INF 1e9
using namespace std;
int cost[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;
void dijkstra(int s) {
	for (int i = 0; i < V; i++) {
		d[i] = INF;
		used[i] = false;
	}
	d[s] = 0;
	while (true) {
		int v = -1;
		for (int u = 0; u < V; u++) {
			if (!used[u] && ((v == -1) || d[u] < d[v])) {
				v = u;
			}
		}
		//全ての頂点が到達済み
		if (v == -1) {
			break;
		}
		//集合に新たに頂点を追加
		used[v] = true;
		for (int u = 0; u < V; u++) {
			d[u] = min(d[u], d[v] + cost[v][u]);
		}
	}
}

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

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