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 <bits/stdc++.h>
#define _GLIBCXX_DEBUG
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i < (n + 1); ++i)
using namespace std;
using ll = long long;
const int INF = +100100100;
// typedef pair<int,int> P;
const int  WHITE = 0;
const int GRAY =1;
const int BLACK =2;
const int NIL = -1;
const int MAX = 10000;

// 配列のサイズを大きく取りすぎるとエラーが出ないが、実行できなくなる.
vector<int> color(MAX,WHITE), D(MAX,INF);
typedef pair<int,int> node;
vector<node> adj[MAX];
priority_queue<node> HQ;
int n;

void dijkstra(){
    int u = 0;
    D[u] = 0;
    HQ.push(make_pair(0,0));
    while(!HQ.empty()){
        node p = HQ.top();HQ.pop();
        int p_w = p.first;int p_i = p.second;
        if(color[p_i]==BLACK)continue;
        color[p_i]=BLACK;

        for(auto elm : adj[p_i]){
            int v_w = elm.first; int v_i = elm.second;
            if(color[v_i]==BLACK)continue;
            if(D[p_i]+v_w < D[v_i]){
                D[v_i]=D[p_i]+v_w;
                HQ.push(make_pair(D[v_i]*(-1),v_i));
            }
        }
    }
}

int main(){
    cin >> n;
    rep(i,n){
        int id, m;
        cin >> id>>m;
        rep(j,m){
            int opp;cin>>opp;
            int cost; cin >> cost;
            adj[i].push_back(make_pair(cost,opp));
        }
    }
    dijkstra();
    rep(i,n){
        cout<<i << " " << D[i]<<endl;
    }
    return 0;
}

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

const int MAX = 100;
const int INFINITY = 2 << 21;
int n;
int G[MAX][MAX];
int distances[MAX];
int states[MAX];

void dijkstra() {
  int id = 0;
  distances[id] = 0;

  while (1) {
    int min = INFINITY;

    for (int i = 0; i < n; i++) {
      if (states[i] == 0 && distances[i] < min) {
        min = distances[i];
        id = i;
      }
    }

    if (min == INFINITY) break;

    for (int i = 0; i < n; i++) {
      if (states[i] != 0 || G[id][i] == -1) continue;
      if (distances[id] + G[id][i] < distances[i]) {
        distances[i] = distances[id]+ G[id][i];
      }
    }

    states[id] = 1;
  }

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

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n;

  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) G[i][j] = INFINITY;
  }

  int u, k, v, c;
  for (int i = 0; i < n; i++) {
    distances[i] = INFINITY;
    states[i] = 0;
    cin >> u >> k;
    for (int j = 0; j < k; j++) {
      cin >> v >> c;
      G[i][v] = c;
    }
  }

  dijkstra();

  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
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];
  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() {
  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();
 
  return 0;
}