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;

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 << " ";
    if(d[i] == INFTY) cout << -1 << endl;
    else cout << 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;
#define N 100
static const int infinity =(1<<21);
static const int white =0;
static const int gray = 1;
static const int black =2;

int n,M[N][N];

void dijkstra(){
    int min,u;
    int color[N],d[N];
    
    for(int i=0;i<n;i++){
        color[i]=white;
        d[i]=infinity;
    }
    
    d[0]=0;
    
    while(1){
        min=infinity;
        int u=-1;
        for(int i=0;i<n;i++){
            if(color[i]!=black&&d[i]<min){
                min=d[i];
                u=i;
            }
        }
        if(min==infinity)break;
        
        color[u]=black;
        
        for(int v=0;v<n;v++){
            if(color[v]!=black&&M[u][v]!=infinity){
                if(d[u]+M[u][v]<d[v]){
                    d[v]=d[u]+M[u][v];
                    color[v]=gray;
                }
            }
        }
    }
    for(int i=0;i<n;i++)cout<<i<<" "<<d[i]<<endl;
}

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

C++: #include <iostream>
#include <vector>
#include <queue>
#include <functional>
#include <string.h>

using namespace std;
static const int INF = 1e9;
typedef pair<int, int> P;
struct edge
{
	int to;
	int cost;
};

int d[101];
vector<edge> G[101];

void solve()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int to, cost;
			cin >> to >> cost;
			edge e1, e2;
			e1.to = to;
			e1.cost = cost;
			e2.to = u;
			e2.cost = cost;
			G[u].push_back(e1);
			G[to].push_back(e2);
		}
	}
	for (int i = 0; i < 101; ++i)
	{
		d[i] = INF;
	}
	d[0] = 0;
	priority_queue<P, vector<P>, greater<P> > pque;
	pque.push(P(0, 0));
	while (!pque.empty())
	{
		P p = pque.top();
		pque.pop();
		int v = p.second;
		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;
				pque.push(P(d[e.to], e.to));
			}
		}
	}
	for (int i = 0; i < n; ++i)
	{
		cout << i << " " << d[i] << endl;
	}
}

int main()
{
	solve();
	return(0);
}

C++: #include <bits/stdc++.h>
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>
using namespace std;

const int INF = INT_MAX;
typedef pair<int, int> P;

struct edge {int to, cost;};

int dijkstra(const vector<vector<edge>> &graph, int s, int g ) {
  vector<int> d(graph.size(), INF);
  d[s] = 0;
  priority_queue<P, vector<P>, greater<P>> now;
  now.push(P(0, s));
  
  while(!now.empty()) {
    int pos = now.top().second; now.pop();
    if (pos == g) {
      for(int i = 0; i <= g; i++) {
        cout << i << " " << d[i] << endl;
      }
      return INF;
    }
    for(auto ed: graph[pos]) {
      if(d[ed.to] > d[pos] + ed.cost) {
        d[ed.to] = d[pos] + ed.cost;
        now.push(P(d[ed.to], ed.to));
      }
    }
  }
  return INF;
}
  
int main() {
  int num;
  cin >> num;
  vector<vector<edge>> graph(num, vector<edge>());
  int f, n, k, v, c;
  for(int i = 0; i < num; i++) {
    cin >> f >> k;
    for(int j = 0; j < k; j++) {
      cin >> v >> c;
      graph[f].push_back(edge{v, c});
      // graph[v].push_back(edge{f, c});
    }
  }
  dijkstra(graph, 0, num - 1);
  return 0;
}