Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#define MAX_V 100
#define INF 1e9
using namespace std;
int cost[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;
void dijkstra(int s) {
	for (int i = 0; i < V; i++) {
		d[i] = INF;
		used[i] = false;
	}
	d[s] = 0;
	while (true) {
		int v = -1;
		for (int u = 0; u < V; u++) {
			if (!used[u] && ((v == -1) || d[u] < d[v])) {
				v = u;
			}
		}
		//全ての頂点が到達済み
		if (v == -1) {
			break;
		}
		//集合に新たに頂点を追加
		used[v] = true;
		for (int u = 0; u < V; u++) {
			d[u] = min(d[u], d[v] + cost[v][u]);
		}
	}
}

int main() {
	for (int i = 0; i < V+3; i++) {
		for (int j = 0; j < V+3; j++) {
			cost[i][j] = INF;//iからjへの辺の重さ
		}
	}
	cin >> V;
	for (int i = 0; i < V; i++) {
		int u;
		cin >> u;
		int k;
		cin >> k;
		for (int j = 0; j < k; j++) {
			int v;
			cin >> v;
			int c;
			cin >> c;
			cost[u][v] = c;
		}
	}
	dijkstra(0);

	for (int i = 0; i < V; i++) {
		cout << i << " " << d[i] << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<queue>
#define INF 100000000
using namespace std;
int main(){
  int n;cin>>n;
  int u,k,v,c;
  int mp[101][101],d[101];
  for(int i=0;i<=100;i++){
    d[i]=INF;
    for(int j=0;j<=100;j++)mp[i][j]=INF;
  }
    while(u!=n-1){
    cin>>u>>k;
    for(int i=0;i<k;i++){
      cin>>v>>c;
      mp[u][v]=c;
    }
  }
    
    queue<int>p;
    int mn,s,t[101]={},cn=n-1;
    d[0]=0,t[0]=1,p.push(0);
    while(cn){
      s=p.back();
      mn=INF;
      for(int i=0;i<n;i++){
	if(t[i]==0){
	  if(d[i]>d[s]+mp[s][i])d[i]=d[s]+mp[s][i];
	  if(mn>d[i])mn=d[i],k=i;
	}
      }
      if(mn!=INF)cn--,t[k]=1,p.push(k);
      else p.pop();
    }
    for(int i=0;i<n;i++)cout<<i<<" "<<d[i]<<endl;
    
  return 0;
}

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

const int NOTV = 0;
const int VIST = 1;
const int NMAX = 100;
const int VMAX = 2000;
const int NILL = -1;
const int INF = 1 << 21;
int a[NMAX][NMAX];  //??£??\??????
int n;
//priority_queue <greater<int>> pq;

void dijkstra(){

	int p[NMAX];
	int d[NMAX];
	int vst[NMAX];
	int minc;
	for (int i = 0; i < n; i++) {
		vst[i] = NOTV;
		d[i] = INF;
	}
	d[0] = 0;
	p[0] = -1;
	while (1) {
		minc = INF;
		int u;
		for (int i = 0; i < n; i++) {
			if (minc > d[i] && vst[i]==NOTV) {
				u = i;
				minc = d[i];
			}
		}
		if (minc == INF) break;
		vst[u] = VIST;
		for (int v = 0; v < n; v++) {
			if (vst[v] == NOTV && a[u][v] != INF) {
				if (d[u] + a[u][v] < d[v]) {
					d[v] = d[u] + a[u][v];
					vst[v] = NOTV;
				}
			}

		}
	}
	for (int i = 0; i < n; i++) {
		cout << i << ' ' << ((d[i] == INF) ? -1 : d[i]) << endl;
	}
}

int main() {
	cin >> n;
	int um;
	int uo;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			a[i][j] = INF;
		}
	}
	for (int i = 0; i < n; i++) {
		cin >> um;
		int k;
		cin >> k;
		for (int j = 0; j < k; j++) {
			cin >> uo;
			cin >> a[um][uo];
		}
		
	}
	
	dijkstra();
	return 0;
}

C++: import java.util.Arrays;
import java.util.Scanner;

public class Main {
	static int N;
	static int W[][], distance[], state[];
	static final int INF = 1000000000;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();

		W = new int[N][N];
		distance = new int[N];
		state = new int[N];

		for (int i = 0; i < N; i++) {
			for (int j = 0; j < N; j++) {
				W[i][j] = INF;
			}
		}

		for (int i = 0; i < N; i++) {
			sc.nextInt(); // u を読み飛ばし
			int k = sc.nextInt();
			for (int j = 0; j < k; j++) {
				int v = sc.nextInt();
				int c = sc.nextInt();
				W[i][v] = c;
			}
		}
		dijkstra(0);
		for (int i = 0; i < N; i++) {
			System.out.println(i + " " + distance[i]);
		}
	}

	private static int min(int a, int b) {
		if (a < b)
			return a;
		return b;
	}

	private static void dijkstra(int start) {
		// Arrasys.fill は配列の初期化がデキル便利メソッド．ただし1次元配列のみ
		Arrays.fill(distance, INF);
		Arrays.fill(state, 0);
		distance[start] = 0;

		int p = 0; // 確定頂点番号を保存する変数
		for (int step = 0; step < N; step++) {
			int minimum = INF;
			for (int x = 0; x < N; x++) {
				if (state[x] == 0 && distance[x] < minimum) {
					p = x;
					minimum = distance[x];
				}
			}
			if (minimum == INF) {
				System.err.println("Disconnected Graph!\n");
				System.exit(-1);
			}
			state[p] = 1;
			for (int x = 0; x < N; x++)
				distance[x] = min(distance[x], distance[p] + W[p][x]);
		}

	}
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

static const int MAX = 100;
static const int INFTY = 1000000000;
static const int WHITE = 0, BLACK = 2;

int n;
int A[MAX][MAX];
int d[MAX], color[MAX];

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

	d[0] = 0;

	while (1) {
		int minv = INFTY, u = -1;
		for (int i = 0; i < n; i++) { 
			if (d[i] < minv && color[i] != BLACK) {
				minv  = d[i];
				u = i;
			}
		}
		if (u == -1) break;
		color[u] = BLACK;

		for (int j = 0; j < n; j++) { 
			if (A[u][j] < INFTY && color[j] != BLACK) {
				d[j] = min(d[j], d[u] + A[u][j]);
			}
		}
	}
}

int main() {
	cin >> n;
	for (int i = 0; i < n; i++)	{
		for (int j = 0; j < n; j++) {
			A[i][j] = INFTY;
		}
	}
	
	for (int i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int t;
			cin >> v >> t;
			A[u][v] = t;
		}
	}

	sssp();

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

	return 0;
}