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<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;
}

C++: #define _CRT_SECURE_NO_WARNINGS

#include<iostream>
#include<functional>
#include<algorithm>
#include<stack>
#include<queue>
#include<iomanip>
#include<set>
#include<map>
#include<utility>
#include<string>
#include<vector>

using namespace std;

#define LL long long
const int dx[4] = { 1,-1,0,0 };
const int dy[4] = { 0,0,1,-1 };
bool OOA(int x, int y, int H, int W) { return (0 <= x && x<H) && (0 <= y && y<W); }

struct Edge{
	int fr,to,val;
	bool operator < (Edge x){
		return (val<x.val);
	}
};

struct Graph {
	struct Edge {
		int fr, to, val;
		Edge(int f, int t, int v) :fr(f), to(t), val(v) {}
	};

	int V, E, t;
	vector<int>cost;
	vector<bool>vzt;
	vector<vector<pair<int,int>>>adj;//to,val
	void init(int n,int dflt) {//dflt!=0
		t = 1;
		V = n;
		adj = vector<vector<pair<int,int>>>(V + 1);
		cost = vector<int>(V + 1, dflt);
		vzt = vector<bool>(V + 1, false);
		return;
	}

	void Dijkstra(int s){
		priority_queue<pair<int,int>>pq;
		pq.push({s,0});
		cost[s]=0;
		while(!pq.empty()){
			auto now=pq.top().first,ncos=pq.top().second;
			pq.pop();
			for(int i=0;i<adj[now].size();i++){
				if(cost[adj[now][i].first]>cost[now]+adj[now][i].second){
					cost[adj[now][i].first]=cost[now]+adj[now][i].second;
					pq.push({ adj[now][i].first,cost[adj[now][i].first] });
				}
			}
		}
		return;
	}
};

int n;
Graph G;

int main() {
	cin >> n;
	G.init(n,(1<<30));
	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.adj[u].push_back({v,c});
		}
	}
	G.Dijkstra(0);
	for(int i=0;i<n;i++){
		cout<<i<<" "<<G.cost[i]<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class node{
public:
  int to;
  int from;
  int cost;
};

int main(void) {

  int n; scanf("%d", &n);
  vector<node> v;
  for(int i=0; i<n; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    for(int j=0; j<k; j++){
      int vv, c;
      scanf("%d %d", &vv, &c);
      node t;
      t.from = u;
      t.to = vv;
      t.cost = c;
      v.push_back(t);
    }
  }

  vector<int> dist(n, inf);
  vector<bool> vis(n, false);

  priority_queue< pair<int, int> > pq;
  pq.push(make_pair(0, 0));
  dist[0] = 0;
  vis[0] = true;
  while( !pq.empty() ){
    pair<int, int> pos = pq.top();
    pq.pop();

    for(int i=0; i<v.size(); i++){
      if( pos.second != v[i].from ) continue;
      // if( vis[ v[i].to ] ) continue;
      if( dist[v[i].to] < dist[v[i].from] + v[i].cost ) continue;

      dist[v[i].to] = min(dist[v[i].to], dist[v[i].from] + v[i].cost);
      pq.push(make_pair(dist[v[i].to], v[i].to));
      vis[v[i].to] = true;
    }

  }

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

  return 0;
}

// EOF