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 RangeFor(i,n) for(int i=0; i<n; ++i)
#define RvRngFor(i,n) for(int i=n-1; i>=0; --i)

#include <iostream>
#include <vector>
#include <queue>
#include <utility>
#include <limits>

using std::vector;
using std::cin;
using std::priority_queue;
using std::pair;
using std::make_pair;


vector<int> sssp(vector<vector<pair<int, int> > > c, int start_node = 0){
    int n = c.size();
    priority_queue<pair<int, int>, vector<pair<int,int> >, std::greater<pair<int, int>> > pq;
    vector<int> temp_dist(n, std::numeric_limits<int>::max());
    pq.push(make_pair(0, start_node));

    for(;!pq.empty();pq.pop()){
        auto t = pq.top();
        auto d = t.first;
        auto u = t.second;


        if(d < temp_dist[u]){
            temp_dist[u] = d;
            auto k = c[u].size();
            RangeFor(j, k) {
                pq.push(make_pair(d + c[u][j].second, c[u][j].first));
            }
        }
    }

    return temp_dist;
}

int main(){
    int n; cin >> n;
    vector<vector< pair<int,int> > > c(n);
    RangeFor(i, n) {
        int u;
        cin >> u;
        int k;
        cin >> k;
        c[u] = vector<pair<int, int> >(k);
        RangeFor(j, k) {
            int v;
            cin >> v;
            int d;
            cin >> d;
            c[u][j] = make_pair(v, d);
        }
    }

//    RangeFor(i, n){
//        RangeFor(j, c[i].size()){
//            std::cout << c[i][j].first << ' ' << c[i][j].second;
//        }
//        std::cout << std::endl;
//    }

    auto res = sssp(c);
    RangeFor(i, n){
        std::cout << i << ' ' << res[i] << std::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 (unsigned int j = 0; j < adj[u].size(); j++) {
			int v = adj[u][j].first;
			if (color[v] == BLACK)continue;
			if (d[v] > d[v] + 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++: #include <bits/stdc++.h>
using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP0(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
#define REP1(i,n) for(int i=1, i##_len=(n); i<=i##_len; ++i)
#define RREP0(i,n) for(int i=n-1; i>=0; --i)
#define RREP1(i,n) for(int i=n; i>=1; --i)

#define SORT(c) sort((c).begin(),(c).end())
#define whole(f,x,...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x)
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define CLR(a) memset((a), 0 ,sizeof(a))

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

typedef long long LL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;

const int INTINF = 2147483647;
const LL LLINF = 9223372036854775807;
const double EPS = 1e-10;
const double PI  = acos(-1.0);
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
const int MAX = 10000;

int n;
std::vector<PII> adj[MAX];

struct init{
    init(){
        cin.tie(0); ios::sync_with_stdio(0); cout<<fixed<<setprecision(20);
    };
} init;


void dijkstra(){
  priority_queue<PII> PQ;  // <cost, vertex> のPQ
  int color[MAX];
  int d[MAX];  // d[i] : mincost from s to i
  REP0(i,n){
    d[i] = INTINF;
    color[i] = WHITE;
  }
  d[0] = 0;
  PQ.push(MP(0,0));
  color[0] = GRAY;
  while ( !PQ.empty() ) {
    PII f = PQ.top(); PQ.pop(); //最小となる頂点と重み
    int u = f.second;
    color[u] = BLACK;

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

    REP0( j, adj[u].size() ){ // uに隣接する頂点をみていく
      int v = adj[u][j].first;
      if ( color[v] == BLACK ) continue;
      if ( d[v] > d[u] + adj[u][j].second ){ // does it renew shortest path to v
        d[v] = d[u] + adj[u][j].second;
        PQ.push(MP(d[v]*-1, v));
        color[v] = GRAY;
      }
    }
  }

  REP0(i,n){
    std::cout << i << " " << (d[i] == INTINF ? -1 : d[i]) << '\n';
  }
}


void input(){
  int u,k,v,c;
  std::cin >> n;
  REP0(i,n){
    std::cin >> u >> k;
    REP0(j,k){
      std::cin >> v >> c;
      adj[u].PB(MP(v,c));
    }
  }
}


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