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>
#include <cstdio>
using namespace std;
int a[100][100], n;
int d[200];
void duyet(int u)
{
    for(int v=0; v<n; v++)
    {
        if(a[u][v]>0 && d[v]>(d[u]+a[u][v]))
        {
            d[v]=d[u]+a[u][v];
            duyet(v);
        }
    }
}
int main()
{
    long long int s,t,u;
    cin>>n;
    for(int i=0; i<n; i++)
    {
        cin>>s>>t;
        for(int j=1; j<=t; j++)
        {
            cin>>s>>u; a[i][s]=u;
        }
        d[i]=1e6;
    }
    d[0]=0;
    duyet(0);
    for(int i=0; i<n; i++)
    {
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
#include<climits>
using namespace std;

struct Edge{ int to,cost; };

typedef pair<int,int> P;
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

void dijkstra(Graph &G,vector<int> &d,int n,int s){
	priority_queue< P, vector<P>, greater<P> > que;
	fill(d.begin(),d.end(),INT_MAX);
	d[s]=0;
	que.push(P(0,s));
	
	while(!que.empty()){
		P p=que.top();
		que.pop();
		
		int a=p.second;
		if (d[a]<p.first){
			continue;
		}
		for (int i=0;i<G[a].size();i++){
			Edge e = G[a][i];
			if (d[e.to]>d[a]+e.cost){
				d[e.to]=d[a]+e.cost;
				P p2=P(d[e.to],e.to);
				que.push(p2);
			}
		}
	}
}

int main(){
	int n,i,j,k;
	vector<int> d(n);
	Edge e;
	
	cin >> n;
	
	Graph G(n);
	
	for (i=0;i<n;i++){
		cin >> k >> k;
		for (j=0;j<k;j++){
			cin >> e.to >> e.cost;
			G[i].push_back(e);
		}
	}
	
	dijkstra(G,d,n,0);
	
	for (i=0;i<n;i++){
		cout << i << " " << d[i] << endl;
	}
	
	return 0;
}

C++: #include<iostream>
int main(){
  int u,k,C,V,A[1000][1000],D[1000][1000],n;
  std::cin >> n;
  for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = 200001;
  for(int i=0;i<n;i++){ 
    std::cin >> u >> k;
    for(int j=0;j<k;j++){
      std::cin >> 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]= std::min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)std::cout << i << " " << D[0][i] << std::endl;
  return 0;
}

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


#define MAX 100


using namespace std;


int main()
{
    int n;
    vector< vector<int> > adj(MAX, vector<int>(MAX, -1));
    cin >> n;
    for (int i = 0; i < n; i++) {
        int id, k;
        cin >> id >> k;
        for (int j = 0; j < k; j++) {
            int v, c;
            cin >> v >> c;
            adj[id][v] = c;
        }
    }

    vector<int> min_costs(MAX, INT_MAX);
    vector<bool> in_tree(MAX, false);
    vector<int> parent(MAX, false);

    min_costs[0] = 0;
    for (int tc = 0; tc < n; tc++) {
        int min_cost = INT_MAX;
        int closest_v = -1;
        for (int i = 0; i < n; i++) {
            if (min_cost > min_costs[i] && !in_tree[i]) {
                min_cost = min_costs[i];
                closest_v = i;
            }
        }

        in_tree[closest_v] = true;

        for (int i = 0; i < n; i++) {
            if (adj[closest_v][i] < 0)
                continue;

            int w = min_cost + adj[closest_v][i];
            if (!in_tree[i] && min_costs[i] > w) {
                min_costs[i] = w;
                parent[i] = min_cost;
            }
        }
    }

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

    return 0;
}

C++: #include"iostream"
#include"algorithm"
#include"cstdio"
#include"cstring"
#include"string"
#include"vector"
#include"queue"
#include"map"
#include"set"
#include"stack"
#include"cmath"
using namespace std;
#define INF 0xfffffff
const int maxn = 100000 + 10;
const int maxm = 500000 + 10;
int n, m;
int s,t;
int fir[maxn], nxt[maxm], to[maxm], val[maxm], cnt;
void add_edge(int u, int v, int w)
{
    nxt[++cnt] = fir[u];
    fir[u] = cnt;
    to[cnt] = v;
    val[cnt] = w;
}
struct Node 
{
    int d, id;
    Node(){}
    Node(int d, int id) : d(d), id(id){}
    bool operator < (const Node& rhs) const
      {
        return d > rhs.d;
      }
};
int dis[maxn], vis[maxn];
void Dijkstra(int s)
{
    for(int i = 1; i <= n; i++) dis[i] = INF;
    dis[s]=0;
    priority_queue<Node> Q;
    Q.push(Node(0,s));
    while(!Q.empty()) 
      {
        Node u = Q.top(); Q.pop();
        if(vis[u.id]) continue;
        vis[u.id] = 1;
        for(int e = fir[u.id]; e; e = nxt[e]) 
          {
            int v = to[e], w = val[e];
            if(u.d + w < dis[v]) 
              {
                dis[v] = u.d + w;
                Q.push(Node(dis[v],v));
              }
          }
      }
}
int main()
{
		cin >> m;
		for(int i=0; i<m; i++)
        {
			int k;
			memset(vis,0,sizeof(vis));
			scanf("%d%d",&n,&k);
			for(int j=0;j<k;j++)
			{
            int  b, c;
            cin >> b >> c;
            add_edge(n,b,c);
			}
			Dijkstra(0);
			printf("%d %d\n",n,dis[n]);
        }
    return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

#define INF 1000000

int n;
int cost[110][110], d[110];
bool used[110];

void dijkstra(int s){

  for(int i = 0;i < n;i++) d[i] = INF;
  for(int i = 0;i < n;i++) used[i] = false;
  
  d[s] = 0;
  
  while(true){
    int v = -1;
    
    for(int u = 0;u < n;u++){
      if(!used[u] && (v == -1 || d[u] < d[v])) v = u;
    }
    
    if(v == -1) break;
    used[v] = true;
    
    for(int u = 0;u < n;u++){
      d[u] = min(d[u], d[v] + cost[v][u]);
    }
  }
}

int main(){
  
  int u, k, v, c;
  
  cin >> n;
  for(int i = 0;i < n;i++){
    for(int j = 0;j < n;j++){
      cost[i][j] = INF;
    }
  }
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> v >> c;
      cost[u][v] = min(cost[u][v], c);
    }
  }
  
  dijkstra(0);
  
  for(int i = 0;i < n;i++) cout << i << " " << d[i] << endl;
  
  return 0;
}

C++: #include <cstdio>
#include <iostream>
using namespace std;
#define INF 0xfffffff
int dis[200][200];
int main()
{
	int n;
	while(scanf("%d",&n)!=EOF)
	{
		for(int i=0;i<n;i++)
            for(int j=0;j<n;j++)
            {
                if(i==j) 
				dis[i][j]=0;
                else dis[i][j]=INF;
            }
		for(int i=0;i<n;i++)
		{
			int a,b,c;
			scanf("%d",&a);
			int t;
			scanf("%d",&t);
			for(int j=0;j<t;j++)
			{
				scanf("%d %d",&b,&c);
				dis[a][b]=min(c,dis[a][b]);
			}
		}
		for(int k = 0; k < n; k++)  //枚举中间点（必须放最外层）
		  for(int i = 0; i < n; i++)  //枚举端点i
		    if(i != k)
		      for(int j = 0; j < n; j++)  //枚举端点j
		        if(i != j && j != k && dis[i][j] > dis[i][k] + dis[k][j])
		          dis[i][j] = dis[i][k] + dis[k][j];
		int f,g;
		f=0;g=0;
		dis[0][0]=0;
		for(g=0;g<n;g++)
		{
			printf ("%d %d\n",g,dis[f][g]);
		}
	}
}