Go: package main

import (
	"bufio"
	"container/heap"
	"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
const INF = 1 << 60

type Edge struct {
	to, cost int
}

type Node struct {
	id, cost int
}

type PQ []Node

func (pq PQ) Len() int           { return len(pq) }
func (pq PQ) Less(i, j int) bool { return pq[i].cost < pq[j].cost }
func (pq PQ) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }

func (pq *PQ) Push(x interface{}) {
	*pq = append(*pq, x.(Node))
}

func (pq *PQ) Pop() interface{} {
	old := *pq
	n := len(old)
	x := old[n-1]
	*pq = old[0 : n-1]
	return x
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		E[id] = make([]Edge, k)
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id][j] = Edge{to, cost}
		}
	}

	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	done := make([]bool, N)
	pq := &PQ{}
	heap.Init(pq)
	d[0] = 0
	heap.Push(pq, Node{0, 0})
	for pq.Len() > 0 {
		cur := heap.Pop(pq).(Node).id
		if done[cur] {
			continue
		}
		done[cur] = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+d[cur]
			if !done[to] && cost < d[to] {
				d[to] = cost
				heap.Push(pq, Node{to, cost})
			}
		}
	}

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

C++: //Dijkstra
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
#include<vector>
using namespace std;
typedef pair<int, int> P;
int n, dis[10001], n_left;
vector< vector<P> > G(10001);
priority_queue< P, vector<P>, greater<P> > heap;
bool visited[10001];

int main(){
    int u, v, k, w;

    scanf("%d", &n);
    n_left = n;
    for(int i=0; i<n; i++){
        scanf("%d %d", &u, &k);
        for(int j=0; j<k; j++){
            scanf("%d %d", &v, &w);
            G[u].push_back(P(w, v));
        }
    }
    memset(visited, 0, sizeof(visited));
    memset(dis, 127, sizeof(dis));

    dis[0] = 0;
    heap.push(P(0, 0));
    while(!heap.empty() && n_left>0){
        P top = heap.top();
        heap.pop();
        if(!visited[top.second]){
            u = top.second;
            visited[u] = true;
            --n_left;
            for(int i=0; i<G[u].size(); i++){
                v = G[u][i].second;
                w = dis[u] + G[u][i].first;
                if(!visited[v] && w < dis[v]){
                    heap.push(P(w, v));
                    dis[v] = w;
                }
            }
        }
    } 
    for(int i=0; i<n; i++){
        printf("%d %d\n", i, dis[i]);
    }
    return 0;
}

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

#define INF 2000000000

typedef pair<int, int> P;
struct edge{ int to, cost;};

int n;
vector<edge> G[10000];
int d[10000];

void dijkstra(int s){
  
  priority_queue<P, vector<P>, greater<P> > que;
  
  for(int i = 0;i < n;i++) d[i] = INF;
  d[s] = 0;
  que.push(P(0, s));
  
  while(!que.empty()){
    P p = que.top();
    que.pop();
    int v = p.second;
    
    if(d[v] < p.first) continue;
    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;
        que.push(P(d[e.to], e.to));
      }
    }
  }
}

int main(){
  
  int u, k;
  edge e;
  
  cin >> n;
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> e.to >> e.cost;
      G[u].push_back(e);
    }
  }
  
  dijkstra(0);
  
  for(int i = 0;i < n;i++) cout << i << " " << d[i] << endl;
  
  return 0;
}

C++: // ALDS1_12_C.cpp
// Graph II - Single Source Shortest Path II
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <queue>
using namespace std;

struct Node {
    int v;
    int c;
    Node(int v, int c): v(v), c(c) {}
};

const int maxN = 10000;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int INF = (1<<21);
vector<Node> G[maxN];
vector<int> dist(maxN, INF);
vector<int> p(maxN);
vector<int> color(maxN, WHITE);
priority_queue<pair<int, int>> mq;
int n;

void dijkstra(int x)
{
    dist[x] = 0;
    p[x] = -1;
    mq.push({-dist[x], x});
    while(!mq.empty()) {
        pair<int, int> P = mq.top();
        mq.pop();
        int mindist = -P.first;
        int u = P.second;
        if (color[u] == BLACK) continue;

        for (int i = 0; i < G[u].size(); i++) {
            if (color[u] == BLACK) continue;
            int v = G[u][i].v;
            int c = G[u][i].c;
            if (dist[u] + c < dist[v]) {
                dist[v] = dist[u] + c;
                p[v] = u;
                color[v] = GRAY;
                mq.push({-dist[v], v});
            }
        }
        color[u] = BLACK;
    }
}

int main()
{
    freopen("in7.txt", "r", stdin);
    freopen("out7.txt", "w", stdout);
    cin >> n;
    int u, k;
    int v, c;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            cin >> v >> c;
            G[i].push_back(Node(v, c));
        }
    }
    dijkstra(0);
    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i, dist[i]);
    }
    return 0;
}