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++: #include <iostream>
#include <vector>
#include <climits>
#include <queue>

using namespace std;

const int kSize = 100001;

vector<int> V;

struct Node {
    int to;
    int weight;

    Node(int _to, int _weight) {
        to = _to;
        weight = _weight;
    }
};

int n;
vector<Node> adj[kSize];
bool isMarked[kSize];
int tree[kSize];
int dis[kSize];

void Dijkstra(int s) {
    dis[s] = 0;
    priority_queue<pair<int, int>, vector<pair<int, int> >, greater<> > pq;

    pq.push(make_pair(s, 0));
    //isMarked[s] = true;
    tree[s] = s;

    while (!pq.empty()) {
        pair<int, int> p = pq.top();
        pq.pop();
        int from = p.first;
        for (int i = 0; i < adj[from].size(); ++i) {
            int to = adj[from][i].to;
            if (dis[from] + adj[from][i].weight < dis[to]) {
                dis[to] = dis[from] + adj[from][i].weight;
                tree[to] = from;
                pq.push(make_pair(to, dis[to]));
            }
        }
    }

}

int main() {
    fill(isMarked, isMarked + kSize, false);
    fill(dis, dis + kSize, INT_MAX);
    cin >> 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;
            adj[u].emplace_back(v, c);
        }
    }

    Dijkstra(0);
    for (int i = 0; i < n; ++i) {
        cout << i << " " << dis[i] << endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
static const int INF=1000000;

int n;
vector<pair<int,int> > nex[10000];

void dijkstra(){ 
  priority_queue<pair<int,int> >PQ;
  int d[10000];
  int color[10000];  
  for(int i=0;i<n;i++){
    d[i]=INF;
    color[i]=0;
  }
  
  color[0]=1;
  d[0]=0;
  PQ.push(make_pair(0, 0));
  
  while( !PQ.empty() ){
    pair<int,int> f = PQ.top();PQ.pop();
    int u =f.second;
    color[u]=2;
    if(d[u] < f.first *(-1)) continue;
    
    for(int j=0;j<nex[u].size();j++){
      int v=nex[u][j].first;
      if(color[v] == 2) continue;
      if(d[v]>d[u]+nex[u][j].second){
        d[v]=d[u]+nex[u][j].second;
        PQ.push(make_pair(d[v]*(-1),v));
        color[v]=1;
      }
    }
  }
  for(int i=0;i<n;i++){
    cout<<i<<" "<<(d[i] == INF ?:d[i])<<endl;
  }
}


int main(){
  cin>>n;
  int u,k,v,c;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
      nex[u].push_back(make_pair(v,c));
    }
  }
  
  dijkstra();
  return 0;
}

C++: #include <vector>
#include <queue>
#include <stdio.h>
#include <iostream>
#include <limits>

using namespace std;

const int MAXN = 10000;
const int INF = numeric_limits<int>::max();

vector< pair<int, int> > G[MAXN];
int dist[MAXN];
int n;

void dijkstra(int start) {
  for (int i = 0; i < n; ++i) dist[i] = INF;

  priority_queue< pair<int, int>, vector< pair<int, int> >, greater< pair<int, int> > > q;
  q.emplace(0, start);
  dist[start] = 0;
  while (!q.empty()) {
    pair<int, int> cur = q.top(); q.pop();
    int v = cur.second;
    int cost = cur.first;
    if (dist[v] < cost) continue;

    for (size_t i = 0; i < G[v].size(); ++i) {
      int u = G[v][i].first;
      int new_cost = G[v][i].second + cost;
      if (dist[u] > new_cost) {
	q.emplace(new_cost, u);
	dist[u] = new_cost;
      }
    }
  }
}
int main () {
  cin >> 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[u].emplace_back(v, c);
    }
  }
  dijkstra(0);
  for (int i = 0; i < n; ++i) {
    cout << i << " " << dist[i] << endl;
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
struct edge{
  int to,cost;
};
typedef pair<int,int> P;
int V;
vector<edge> G[100000];
int d[100000];
void dijkstra(int s){
  priority_queue<P ,vector<P>,greater<P> >que;
  fill(d,d+V,1e9+1);
  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 k,u,v,c;
  cin >> V;
  for(int i=0;i<V;i++){
    cin >> u >> k;
    for(int j=0;j<k;j++){
      cin >> v >> c;
      edge ed;
      ed.to=v;
      ed.cost=c;
      G[u].push_back(ed);
    }
  }
  dijkstra(0);
  for(int i=0;i<V;i++){
    cout << i << " " << d[i] << endl;
  }
  return 0;
}