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 << " " << (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 <iostream>
#include <cmath>
#include <vector>
#include <set>
#include <string>
#include <algorithm>

constexpr int INF = 10000001;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
    int n, u, k, vv, cc;
    std::cin >> n;
    std::vector<std::vector<int>> v(n), c(n);
    std::vector<int> d(n), p(n);
    std::set<int> v_s, s;
    for (int i=0; i<n; i++) {
        std::cin >> u >> k;
        for (int j=0; j<k; j++) {
            std::cin >> vv >> cc;
            v[u].push_back(vv);
            c[u].push_back(cc);
        }
        d[i] = INF;
        v_s.insert(i);
    }
    d[0] = 0;
    //v_s.erase(0);

    while (not v_s.empty()) {
        int mind=INF+1;
        int minnode;
        auto iter = v_s.begin();
        for (int i=0; i<v_s.size(); i++,iter++) {
            if (d[*iter] < mind) {
                mind = d[*iter];
                minnode = *iter;
            }
        }
        v_s.erase(minnode);
        s.insert(minnode);
        for (int i=0; i<v[minnode].size(); i++) {
            if (v_s.find(v[minnode][i]) != v_s.end() and mind + c[minnode][i] < d[v[minnode][i]]) {
                d[v[minnode][i]] = mind + c[minnode][i];
                p[v[minnode][i]] = minnode;
            }
        }
    }

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

    return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <math.h>
#include <algorithm>
using namespace std;
#define ll long long

const ll INF = 7+(1e+9);
typedef int Weight;
struct Edge {  //src:辺の始点,dst:辺の終点,weight:辺の重さ
  int src, dst;
  Weight weight;
  Edge(int src, int dst, Weight weight) :
    src(src), dst(dst), weight(weight) { }
};
bool operator < (const Edge &e, const Edge &f) {
  return e.weight != f.weight ? e.weight > f.weight : //辺は重さが重いものを"小さい"と定義する
    e.src != f.src ? e.src < f.src : e.dst < f.dst;
}
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

//引数 Graph:隣接リスト,r:最小全域木の始点
//戻値 total:最小全域木の重み,T:最小全域木の辺集合
void shortestPath(const Graph &g,vector<vector<Weight> > &dist,vector<vector<int> > &inter) {
  int n = g.size();
  dist.assign(n,vector<Weight>(n,INF));
  for(int i=0;i<n;i++){
    dist[i][i]=0;
  }
  for(int i=0;i<n;i++){
    for(auto f=g[i].begin();f!=g[i].end();f++){
      dist[i][f->dst]=f->weight;
    }
  }
  inter.assign(n, vector<int>(n,-1));
  for(int k=0;k<n;k++){
    for(int i=0;i<n;i++){
      for(int j=0;j<n;j++){
        if (dist[i][j] > dist[i][k] + dist[k][j]) {
          dist[i][j] = dist[i][k] + dist[k][j];
          inter[i][j] = k;
        }
      }
    }
  }
}
void buildPath(const vector<vector<int> > &inter,int s,int t,vector<int> &path) {
  int u = inter[s][t];
  if (u < 0) path.push_back(s);
  else buildPath(inter, s, u, path), buildPath(inter, u, s, path);
}
vector<int> buildPath(const vector<vector<int> > &inter,int s,int t) {
  vector<int> path;
  buildPath(inter, s, t, path);
  path.push_back(t);
  return path;
}


int main(){
  ll n;
  cin>>n;
  Graph g(n);
  ll u,k,v,w;
  for(ll i=0;i<n;i++){
    cin>>u>>k;
    for(ll j=0;j<k;j++){
      cin>>v>>w;
      g[u].push_back(Edge(u,v,w));
    }
  }
  vector<vector<Weight> >dist;
  vector<vector<int> > inter;
  shortestPath(g,dist,inter);
  for(ll i=0;i<n;i++){
    cout<<i<<" "<<dist[0][i]<<endl;
  }
}

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 color[MAX], d[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) {
  	      	  minv = d[i];
  	      	  u = i;
  	      }
      }
      if(u = -1) break;
      color[u] = BLACK;
      for(int i =  0; i < n; i++) {
      	  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;
	int u, k;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][i] = INFTY;
		}
	}
	
	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;
}