Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const (
	INFTY = 1 << 21
	NIL   = -1
)

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph [][]int

func (g *Graph) dikstra(n int) string {
	var (
		u, minv = 0, 0
	)

	d := make([]int, n)
	color := make([]int, n)

	for i := 0; i < n; i++ {
		d[i] = INFTY
		color[i] = WHITE
	}
	d[0] = 0
	color[0] = GRAY

	for {
		minv = INFTY
		u = -1
		for 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 v := 0; v < n; v++ {
			if color[v] != BLACK && (*g)[u][v] != INFTY {
				if d[v] > d[u]+(*g)[u][v] {
					d[v] = d[u] + (*g)[u][v]
					color[v] = GRAY
				}
			}
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d ", i))
		if d[i] == INFTY {
			out.WriteString(fmt.Sprintf("%d\n", -1))
			continue
		}
		out.WriteString(fmt.Sprintf("%d\n", d[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	g := make(Graph, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for j := 0; j < n; j++ {
			g[i][j] = INFTY
		}
	}

	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())

		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			sc.Scan()
			c, _ := strconv.Atoi(sc.Text())

			g[u][v] = c
		}
	}

	return g.dikstra(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repr(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define FORR(i, m, n) for (int i = (m); i >= (n); --i)
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
const ll mod2 = 998244353;
const int INF = 1000000005;
const int MAX = 105;

class edge {
  public:
  int t, c;

  edge(int t = -1, int c = INF): t(t), c(c) {}

  bool operator < (const edge &e) const {
    return c > e.c;
  }
};

vector<edge> to[MAX];
bool seen[MAX];
int d[MAX], n;

void dijkstra(int u) {
  d[u] = 0;
  while (1) {
    seen[u] = true;
    for (edge e: to[u]) {
      if (seen[e.t]) continue;
      d[e.t] = min(d[e.t], d[u] + e.c);
    }

    int mind = INF;
    rep(i, n) {
      if (seen[i]) continue;
      if (d[i] < mind) {
        u = i;
        mind = d[i];
      }
    }

    if (mind == INF) break;
  }
}

int main() {
  cin >> n;
  int u, k;
  edge e;
  rep(i, n) {
    cin >> u >> k;
    rep(j, k) {
      cin >> e.t >> e.c;
      to[u].push_back(e);
    }
  }

  rep(i, n) {
    seen[i] = false;
    d[i] = INF;
  }

  dijkstra(0);

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

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;
}