Go: package main

import (
	"fmt"
	"bufio"
	"os"
	"strconv"
	"container/heap"
)

type Node struct {
	Id int
	Dis int
}

type PriorityQueue []*Node

func (pq PriorityQueue) Len() int { return len(pq) }

func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].Dis < pq[j].Dis
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

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

func (pq *PriorityQueue) Pop() interface{} {
	n := len(*pq)
	pop := (*pq)[n-1]
	*pq = (*pq)[0:n-1]
	return pop
}

func main() {
	var n int
	fmt.Scan(&n)

	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	g := make([][]int, n)
	c := make([][]int, n)
	pq := make(PriorityQueue, 0, n)
	d := make([]int, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		g[u] = make([]int, k)
		c[u] = make([]int, k)
		for j := 0; j < k; j++ {
			sc.Scan()
			g[u][j], _ = strconv.Atoi(sc.Text())
			sc.Scan()
			c[u][j], _ = strconv.Atoi(sc.Text())
		}

		if u == 0 {
			d[u] = 0
		} else {
			d[u] = 1 << 30
		}
		pq.Push(&Node{u, d[u]})
	}
	heap.Init(&pq)

	for pq.Len() > 0 {
		node := heap.Pop(&pq).(*Node)
		for i := 0; i < len(g[node.Id]); i++ {
			nextId := g[node.Id][i]
			nextDis := node.Dis + c[node.Id][i]
			if nextDis < d[nextId] {
				d[nextId] = nextDis
				heap.Push(&pq, &Node{nextId, nextDis})
			}
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		wr.WriteString(strconv.Itoa(i))
		wr.WriteString(" ")
		wr.WriteString(strconv.Itoa(d[i]))
		wr.WriteString("\n")
	}
	wr.Flush()
}

C++: //
//  main.cpp
//
//
//  Created by ???????????? on 2017/10/23.
//  Copyright ?? 2017 ????????????. All rights reserved.
//

#include <iostream>
#include <stdio.h>
#include <queue>
#include <algorithm>


#define n_max 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INFTY 1<<20

using namespace std;

int n, M[n_max][n_max], color[n_max], d[n_max], p[n_max];

void init(){
    int i, j, id, num, node;
    scanf("%d", &n);
    for(i = 0; i < n; i++){
        for(j = 0; j < n; j++){
            M[i][j] = INFTY;
        }
    }
    
    
    for(i = 0; i < n; i++){
        scanf("%d %d", &id, &num);
        for(j = 0; j < num; j++){
            scanf("%d", &node);
            scanf("%d", &M[id][node]);
        }
        color[i] = WHITE;
        d[i] = INFTY;
    }
}

void dijkstra(){
    //initializing
    d[0] = 0;
    p[0] = -1;
    
    priority_queue<pair<int,int> > PQ;
    
    PQ.push(make_pair(0, 0));
    
    int u;
    while(!PQ.empty()){
        //first weight, second idx
        pair<int, int> f= PQ.top(); PQ.pop();
        u = f.second;
        color[u] = BLACK;
        
        if(d[u] < f.first*(-1)) continue;
        
        for(int v = 0; v < n; v++){
            if((color[v] != BLACK) && (M[u][v] != INFTY)){
                if((d[u] + M[u][v]) < d[v]){
                    d[v] = M[u][v] + d[u];
                    PQ.push(make_pair(d[v]*(-1), v));
                    color[v] = GRAY;
                }
            }
        }
    }
    for(int i = 0; i < n; i++){
        cout<<i<<" "<<d[i]<<endl;
    }
}

int main(int argc, const char * argv[]) {
    init();
    dijkstra();
    return 0;
}

C++: #include<iostream>
#include<vector>
#include<queue>
using namespace std;
struct Edge {
    int d, i, j;
    Edge(int d_, int i_, int j_) : d(d_), i(i_), j(j_) {}
    bool operator< (const Edge& right) const{
        return d > right.d;
    }
};
void calc(int t, vector<vector<pair<int, int > > >& G, vector<int>& distance){
    int new_black = t;
    priority_queue<Edge> temp;
    for (int i = 1; i < G.size(); i++) {
        for (int j = 0; j < G[new_black].size(); j++) {
            if (distance[G[new_black][j].first] != -1) continue;
            int dis = G[new_black][j].second + distance[new_black];
            temp.push(Edge(dis, new_black, G[new_black][j].first));
        }
        while (distance[temp.top().j] != -1) temp.pop();
        distance[temp.top().j] = temp.top().d;
        new_black = temp.top().j;
        temp.pop();
    }
}

int main(){
    int n;
    cin >> n;
    vector<vector<pair<int, int> > > G(n);
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        G[u].resize(k);
        for (int j = 0; j < k; j++) {
            int v, c;
            cin >> v >> c;
            G[u][j] = make_pair(v, c);
        }
    }

    vector<int> distance(n, -1);
    distance[0] = 0;
    calc(0, G, distance);
    for (int i = 0; i < n; i++) {
        cout << i << " " << distance[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)   for(int i=0;i<(n);++i)
#define SORT(c)    sort((c).begin(),(c).end())
#define CLR(a)     memset((&a), 0 ,sizeof(a))//clear memory
#define dump(x)    cerr << #x << " = " << (x) << endl;//debug
#define debug(x)   cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#define EPS        1e-10//sample:if((double)>=(double)+EPS)
//cin,cout release
//std::cin.tie(0);
//ios::sync_with_stdio(false);

using namespace std;
int n;
int d[100000];
int color[100000];
vector<pair<int,int> > adj[100000];
#define WHITE 0
#define BLACK 2
#define GRAY 1
void dijkstra(){
  rep(i,n)d[i]=INT_MAX;
  priority_queue< pair<int,int> > PQ;
  rep(i,n)color[i]=WHITE;
  d[0]=0;
  PQ.push(make_pair(0,0));
  color[0]=GRAY;
  while(!PQ.empty()){
    pair<int,int> f=PQ.top();
    PQ.pop();
    int u=f.second;
    color[u]=BLACK;
    if(d[u]<f.first*(-1))continue;
    rep(j,(int)adj[u].size()){
      int v=adj[u][j].first;
      if(color[v]==BLACK)continue;
      if(d[v]>d[u]+adj[u][j].second){
	d[v]=d[u]+adj[u][j].second;
	PQ.push(make_pair(d[v]*(-1),v));
	color[v]=GRAY;
      }
    }
  }
  rep(i,n)cout<<i<<" "<<(d[i]==INT_MAX?-1:d[i])<<endl;
}


int main(){
  int a,b,c,d;
  cin>>n;
  rep(i,n){
    cin>>a>>b;
    rep(j,b){
      cin>>c>>d;
      adj[a].push_back(make_pair(c,d));
    }
  }
  dijkstra();
  return 0;
}

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

static const int MAX = 10000;
static const int INFTY = (1 << 20);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int> > adj[MAX];

void dijkstra() {
    priority_queue<pair<int, int> > PQ;
    int color[MAX], d[MAX];
    for ( int i = 0; i < n; i++ ) {
        d[i] = INFTY;
        color[i] = WHITE;
    }

    d[0] = 0;
    PQ.push(make_pair(0, 0));
    color[0] = GRAY;

    while( !PQ.empty() ) {
        pair<int, int> f = PQ.top();
        PQ.pop();
        int u = f.second;

        color[u] = BLACK;

        if ( d[u] < f.first * (-1) )
            continue;

        for ( int j = 0; j < adj[u].size(); j++ ) {
            int v = adj[u][j].first;
            if ( color[v] == BLACK )
                continue;
            if ( d[v] > d[u] + adj[u][j].second ) {
                d[v] = d[u] + adj[u][j].second;
                PQ.push(make_pair(d[v] * (-1), v));
                color[v] = GRAY;
            }
        }
    }

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

void solve() {
    int k, u, v, c;

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

    dijkstra();
}

int main() {
    // freopen("infile", "r", stdin);
    // freopen("outfile", "w", stdout);
    solve();
    return 0;
}