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 <bits/stdc++.h>
using namespace std;

const int INF = numeric_limits<int>::max();

struct edge {
    int u, v, c;
};
struct Graph {
    vector<edge> es;
    vector<int> d;
    Graph(int n) {
        d.assign(n, INF);
    }
};

int main()
{
    int n;
    cin >> n;
    Graph g(n);
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v, c;
            cin >> v >> c;
            g.es.push_back({u, v, c});
        }
    }

    g.d[0] = 0;
    for (int i = 0; i < n - 1; i++) {
        for (edge e : g.es) {
            if (g.d[e.u] != INF && g.d[e.v] > g.d[e.u] + e.c) {
                g.d[e.v] = g.d[e.u] + e.c;
            }
        }
    }

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

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long
int e[111][111],d[111];
int used[111];
signed main(){
  int n;
  cin>>n;
  int INF=1LL<<55LL;
  for(int i=0;i<n;i++)
    for(int j=0;j<n;j++)
      e[i][j]=INF;
  for(int i=0;i<n;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0;j<k;j++){
      int v,c;
      cin>>v>>c;
      e[u][v]=min(e[u][v],c);
    }
  }
  memset(used,0,sizeof(used));
  for(int i=0;i<n;i++) d[i]=INF;
  d[0]=0;
  while(1){
    int u=-1;
    for(int i=0;i<n;i++){
      if(used[i]) continue;
      if(d[i]==INF) continue;
      if(u<0||d[i]<d[u]) u=i;
    }
    if(u<0) break;
    used[u]=1;
    for(int i=0;i<n;i++){
      d[i]=min(d[i],d[u]+e[u][i]);
    }
  }
  for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
  return 0;
}

C++: #include<stdio.h>
#include<string.h>
#include<algorithm>
#include<map>
#include<queue>
#include<iostream>
#include <iomanip>
#include<string>
#include<math.h>
using namespace std;
const int inf = 0x3f3f3f3f;
int m, n, i, j, k, a, b, d;
int dis[1010][1010],e[1010], r[1010];
void init()
{
	memset(dis, inf, sizeof(dis));
	for (i = 0; i < 1010; i++)
		dis[i][i] = 0;
}
void add(int a, int b, int c)
{
	dis[a][b] = min(dis[a][b], c);
}
void floyd()
{
	for (k = 0; k < n; k++)
		for (i = 0; i < n; i++)
			for (j = 0; j < n; j++)
				if (dis[i][j] > dis[i][k] + dis[k][j])
					dis[i][j] = dis[i][k] + dis[k][j];
}
int main()
{
	int x, t, u, v;;
	scanf("%d", &n);
	init();
	for (i = 0; i < n; i++)
	{
		scanf("%d %d", &x, &t);
		for (j = 0; j < t; j++)
		{
			scanf("%d %d", &u, &v);
			add(i, u, v);
		}
	}
	floyd();
	for(i=0;i<n;i++)
		printf("%d %d\n",i, dis[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;
	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){
				tp.first = p.first + cost[p.second][i];
				tp.second = i;
				pq.push(tp);
			}
		}
	}
	return p.first;
}
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;
}