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++: #define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<cmath>
#include<vector>
#include<queue>
using namespace std;

#define REP(i,n) for(int i=0;(i)<(n);(i)++)

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 dist[MAX];
	REP(i, n) {
		dist[i] = INFTY;
		color[i] = WHITE;
	}

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

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

	REP(i, n) {
		cout << i << " " << (dist[i] == INFTY ? -1 : dist[i]) << endl;
	}
}

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

	dijkstra();

	return 0;
}

C++: #include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
const int MAX_N =10010;
int d[MAX_N];//最短距離
struct edge{
	int from,to,cost;
	edge(int _from,int _to,int _cost){
		from =_from;
		to =_to;
		cost =_cost;
	}
};
vector<edge> es;//辺
int V,E;//頂点数と変数

void bellman(int s){
	for(int i =0;i <V;i++)d[i]=INF;
	d[s] = 0;
	while(true){
		bool update=false;
		for(int i =0;i <E;i++){
			edge e =es[i];
			if(d[e.from]!=INF&&d[e.to] >d[e.from] +e.cost){
				d[e.to] =d[e.from]+e.cost;
				update =true;
			}
		}
		if(!update)break;
	}
}
int main(){
	cin>>V;
	E = 0;
	for(int i =0;i < V;i++){
		int node,k;
		cin>>node>>k;
		for(int j =0;j <k;j++){
			int x,c;
			cin>>x>>c;
			es.push_back(edge(node,x,c));
			E++;
		}
	}
	bellman(0);
	for(int i=0;i < V;i++){
		cout <<i<<" "<<d[i]<<endl;
	}
	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;
}