Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

C++: #include<iostream>
#include<cstdio>
#define INF 200001 
using namespace std;
  
int main(){
 int u,k,C,V,A[1000][1000],D[1000][1000],n;
  scanf("%d",&n);
   for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = INF;
   
  for(int i=0;i<n;i++){
      scanf("%d %d",&u,&k);    
      for(int j=0;j<k;j++){
    scanf("%d %d",&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]= min(D[i][j],D[i][k] + D[k][j]);
 
  for(int i=0;i<n;i++)printf("%d %d\n",i,D[0][i]);
  
  return 0;
}

C++: #include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <string>
#include <vector>
#define FOR(i, a, b)  for(int i=a;i<=b;++i)
#define rep(i, n) for(int i=0;i<n;++i)
using namespace std;
struct TRAVEL{
  int to;
  int cost;
};
int main(){
  int n;  cin >> n;
  vector<TRAVEL> g[n];
  int d[n];
  bool flag=true;
  rep(i, n){
    int u, k; cin >> u >> k;
    d[i] = 1000000000;
    rep(j, k){
      int v, c; cin >> v >> c;
      g[i].push_back({v, c});
    }
  }
  d[0] = 0;
  while(flag){
    flag = false;
    rep(i, n){
      rep(j, g[i].size()){
        int check = d[g[i][j].to];
        d[g[i][j].to] = min(d[i]+g[i][j].cost, d[g[i][j].to]);
        if(check != d[g[i][j].to])  flag = true;
        cout << "debug : " << i << " " << g[i][j].to << " " << d[g[i][j].to] << endl;
       }
    }
  }
  rep(i, n) cout << i << " "<< d[i] << endl;
  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<bitset>
#include<vector>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<iomanip>
#include <functional>
using namespace std;
typedef long long ll;
const int mod = 1000000007;
const int INF = 1 << 28;
//cout << fixed << std::setprecision(9)
//memset(a, 0, sizeof(a));
//--------------------------

const int MAX = 100;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
int n, M[MAX][MAX];

int dijkstra()
{
	int minv;
	int d[MAX];
	int color[MAX];

	for (int i = 0; i < n; i++) {
		d[i] = INF;
		color[i] = WHITE;
	}

	d[0] = 0;
	color[0] = GRAY;

	while (1) {
		minv = INF;
		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 (M[u][v] != INF && color[v] != BLACK) {
				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] == INF ? -1 : d[i]) << endl;
	}

	return 0;
}

int main()
{
	cin >> n;
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			M[i][j] = INF;

	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;

static const int N = 100;
static const int I=(1<<21);
static const int W= 0;
static const int G =1;
static const int B =2;

int n,M[N][N];

int dij(){
  int minv,d[N],color[N];
  for(int i=0;i<n;i++){
    d[i]=I;
    color[i]=W;
  }

  d[0]=0;
  color[0]=G;

  while(1){
    minv=I;
    int u=-1;
    for(int i=0;i<n;i++){
      if(minv>d[i]&&color[i]!=B){
        u=i;
        minv=d[i];
      }
    }
    if(u==-1)break;
    color[u]=B;
    for(int v=0;v<n;v++){
      if(color[v]!=B&&M[u][v]!=I){
        if(d[v]>d[u]+M[u][v]){
          d[v]=d[u]+M[u][v];
          color[v]=G;
        }
  
      
          
      }
      }
        
    }
  for(int i=0;i<n;i++){
    cout<<i<<" "<<(d[i]==I ? -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]=I;
    }
  }

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

  dij();
  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#define INF 1<<10
using namespace std;
int n;
int A[1000][1000];
int d[1000];
bool used[1000];
int D[1000][1000];

void Init(int f){
  for(int i=0;i<f;i++){
    for(int j=0;j<f;j++)D[i][j] = INF;
  }

}

int main(){
  scanf("%d",&n);
  int u,k,C,V;
  Init(n);
 
  for(int i=0;i<n;i++){
      scanf("%d %d",&u,&k);     
      for(int j=0;j<k;j++){
	scanf("%d %d",&V,&C);
	D[u][V] = C;
	D[V][u] = 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] = min(D[i][j],D[i][k] + D[k][j]); 
  for(int i=0;i<n;i++){
    printf("%d %d\n",i,D[0][i]);
  }

  return 0;
}