Go: package main

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

const BIG_COST = 200000

type Path struct {
	node int
	cost int
}

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

	nNodes := scanInt(sc)

	// 各頂点につながる頂点一覧を得るための隣接リスト
	graph := make([][]Path, nNodes)

	for i := 0; i < nNodes; i++ {
		u := scanInt(sc)
		k := scanInt(sc)
		graph[i] = make([]Path, k)
		for d := 0; d < k; d++ {
			graph[u][d] = Path{
				node: scanInt(sc),
				cost: scanInt(sc),
			}
		}
	}

	// 0 から各頂点への最小コストを保存する配列
	minCosts := make([]int, nNodes)

	minCosts[0] = 0
	for i := 1; i < nNodes; i++ {
		minCosts[i] = BIG_COST
	}

	// 各頂点が調査済みかどうかを保持する配列
	checked := make([]bool, nNodes)

	// 最小コストのパスを高速に取得するためのヒープ。
	// コストが小さいものほどルートに来るようにする。
	heap := NewHeap(func(a, b Path) bool {
		return a.cost < b.cost
	})

	heap.insert(Path{node: 0, cost: 0})
	for heap.size > 0 {
		u := heap.extractMax()

		// 隣接行列を使っていた時とは違い、ヒープには
		// 同じノードへのパスが複数含まれうる。そのため既によりコストの低い
		// パスが見つかっている場合は無視する。
		if minCosts[u.node] < u.cost {
			continue
		}

		checked[u.node] = true

		for _, v := range graph[u.node] {
			cost := v.cost + u.cost
			if !checked[v.node] && cost < minCosts[v.node] {
				minCosts[v.node] = cost
				heap.insert(Path{node: v.node, cost: cost})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i, cost := range minCosts {
		fmt.Fprintf(w, "%d %d\n", i, cost)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

// --- From ALDS1_9_C: Priority Queue

type Heap struct {
	size   int
	heap   []Path
	isHigh func(a, b Path) bool
}

func NewHeap(isHigh func(a, b Path) bool) Heap {
	heap := make([]Path, 1) // 先頭は不使用
	return Heap{size: 0, heap: heap, isHigh: isHigh}
}

func (h *Heap) insert(v Path) {
	h.size += 1
	if h.size > len(h.heap)-1 {
		h.heap = append(h.heap, v)
	} else {
		h.heap[h.size] = v
	}

	for i := h.size; i > 1; {
		parent := i / 2
		if h.isHigh(h.heap[parent], h.heap[i]) {
			break
		}
		h.heap[i], h.heap[parent] = h.heap[parent], h.heap[i]
		i = parent
	}
}

func (h *Heap) extractMax() Path {
	if h.size <= 0 {
		panic("cannot extract from empty heap")
	}

	max := h.heap[1]
	h.heap[1] = h.heap[h.size]
	h.size -= 1
	h.maxHeapify(1)

	return max
}

func (h *Heap) maxHeapify(idx int) {
	left := idx * 2
	right := left + 1
	largest := idx

	if left <= h.size {
		if h.isHigh(h.heap[left], h.heap[idx]) {
			largest = left
		}
		if right <= h.size && h.isHigh(h.heap[right], h.heap[largest]) {
			largest = right
		}
	}

	if largest != idx {
		h.heap[idx], h.heap[largest] = h.heap[largest], h.heap[idx]
		h.maxHeapify(largest)
	}
}

C++: #include <algorithm>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;
static const int NMAX = 100;
#define INF (1 << 30)

int main() {
  int n;
  cin >> n;
  vector<pair<int, int>> adj[NMAX];

  for (int i = 0; i < n; i++) {
    int id, nn;
    cin >> id >> nn;
    for (int j = 0; j < nn; j++) {
      int to, weight;
      cin >> to >> weight;
      // use negative weights for priority_queue
      adj[id].push_back(make_pair(-weight, to));
    }
  }

  bool visited[n];
  int dist[n];
  for (int i = 0; i<n; i++) {
    visited[i] = false;
    dist[i] = -INF;
  }

  priority_queue<pair<int, int>> distQ;

  // add node 0
  for (int i = 0; i < adj[0].size(); i++) {
    distQ.push(adj[0][i]);
    int weight = adj[0][i].first;
    int id = adj[0][i].second;
    dist[id] = weight;
  }
  visited[0] = true;

  while (!distQ.empty()) {
    // find nearest node
    int minnode = distQ.top().second;
    distQ.pop();

    // add node
    visited[minnode] = true;

    // update dist
    for (int i = 0; i < adj[minnode].size(); i++) {
      int weight = adj[minnode][i].first;
      int id = adj[minnode][i].second;

      if (visited[id] == false) {
        int newWeight = dist[minnode] + weight;
        if (-newWeight < -dist[id]) {
          distQ.push(make_pair(newWeight, id));
          dist[id] = newWeight;
        }
      }
    }
  }

  dist[0] = 0;
  for (int i = 0; i < n; i++)
    cout << i << " " << -dist[i] << endl;
}

C++: //
// Created by ?????°?????? on 2016/05/19.
//

#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
const int MAX = 100;
const int INFTY = (1<<21);
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

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

void dijkstra(){
    priority_queue< pair<int,int> > PQ;
    int color[MAX];
    int 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;
    }
}

int main (){
    cin >> n;
    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;
            adj[u].push_back(make_pair(v,c));
        }
    }

    dijkstra();

    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(long long i=0; i<(n); i++)
#define int long long
#define mod 1000000007
#define F first
#define S second
#define P pair<long long,long long>
#define all(a) a.begin(),a.end()
#define INF 1000000000000000000
using namespace std;
struct edge{
    long long to;
    long long cost;
};
signed main(void){
    int n;cin>>n;
    vector<edge>G[n];
    int f,t,c,k;
    rep(i,n){
        cin>>f>>k;
        rep(j,k){
            cin>>t>>c;
            G[f].push_back({t,c});
        }
    }
    vector<int>d(n,INF);d[0]=0;
    //rep(i,n){
      //  rep(j,G[i].size()){
        //    cout<<G[i][j].to<<':'<<G[i][j].cost<<' ';
        //}
        //cout<<endl;
    //}
    priority_queue<P,vector<P>,greater<P>>que;
    que.push(P(0,0));
    while(!que.empty()){
        f=que.top().S;c=que.top().F;que.pop();
        if(d[f]<c)continue;
        rep(i,G[f].size()){
            edge e=G[f][i];
            t=e.to;
            if(d[t]>e.cost+c){
                d[t]=e.cost+c;
                que.push(P(d[t],t));
            }
        }
    }
    rep(i,n){
        cout<<i<<' '<<d[i]<<endl;
    }
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
#include <vector>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1<<21);

enum Color {
  WHITE, GRAY, BLACK
};

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

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

void dijkstra(int s) {
  init();
  d[s] = 0;
  priority_queue<pair<int, int> > PQ;
  PQ.push(make_pair(0, s));

  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[u] + adj[u][j].second < d[v]) {
        d[v] = d[u] + adj[u][j].second;
        PQ.push(make_pair(d[v] * (-1), v));
        color[v] = GRAY;
      }
    }
  }
}


int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    int elem, index, v;
    cin >> v >> elem;
    for (int j = 0; j < elem; j++) {
      int u, cost;
      cin >> u >> cost;
      adj[v].push_back(make_pair(u, cost));
    }
  }
  dijkstra(0);
  for (int i = 0; i < n; i++) {
    cout << i << " " << d[i] << endl;
  }
  return 0;
}