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<cstdio>
#include<vector>
#include<algorithm>
#include<utility>
#include<numeric>
#include<iostream>
#include<array>
#include<string>
#include<sstream>
#include<stack>
#include<queue>
#include<list>
#include<functional>
#define _USE_MATH_DEFINES

#include<math.h>
#include<map>

#define SENTINEL 1000000001

#define min(a,b) (a)>(b)?(b):(a)
#define max(a,b) (a)>(b)?(a):(b)

using namespace std;

typedef pair<int, int> pii;

struct Edge
{
	int t, c;
	Edge(int t,int c):t(t),c(c){}
};

vector<Edge> edges[10000];
int d[10000];

void dijkstra(int n)
{
	priority_queue<pii, vector<pii>, greater<pii>> pq;
	d[0] = 0;
	pq.push(make_pair(0, 0));

	while (!pq.empty())
	{
		pii tp = pq.top();
		pq.pop();

		if (d[tp.second] < tp.first)
		{
			continue;
		}

		for (int i = 0; i != edges[tp.second].size(); i++)
		{
			if (d[tp.second] + edges[tp.second][i].c < d[edges[tp.second][i].t])
			{
				d[edges[tp.second][i].t] = d[tp.second] + edges[tp.second][i].c;
				pq.push(make_pair(d[edges[tp.second][i].t], edges[tp.second][i].t));
			}
		}
	}
}

int main()
{
	int n;
	cin >> n;

	for (int i = 0; i < n; i++)
	{
		d[i] = 100000000;
	}

	for (int i = 0; i < n; i++)
	{
		int id, k;
		cin >> id >> k;
		for (int j = 0; j < k; j++)
		{
			int v, c;
			cin >> v >> c;
		
			edges[id].push_back(Edge(v, c));
		}
	}

	dijkstra(n);

	for (int i = 0; i < n; i++)
	{
		printf("%d %d\n", i, d[i]);
	}

	return 0;
}

C++: #include<bits/stdc++.h>
#define REP(i,n) for(long long i=0;i<n;++i)
#define FOR(i,a,b) for(long long i=a;i<b;++i)
#define F first
#define S second
using namespace std;

typedef pair< int,int > point;
vector< point > graph[10001];
vector< int > v(10001);
int n;
const int INF=1<<30;

void dijkstra(int s){
    priority_queue< point,vector< point >,greater< point > >pq;
    pq.push({0,s});
    fill(v.begin(),v.end(),INF);
    v[s]=0;
    while(!pq.empty()){
        point p=pq.top();
        pq.pop();
        REP(i,graph[p.S].size()){
            int nex=graph[p.S][i].S;
            int cost=p.F+graph[p.S][i].F;
            if(v[nex]>cost){
                v[nex]=cost;
                pq.push({cost,nex});
            }
        }
    }
}

int main(){
    scanf("%d",&n);
    int u,k,to,c;
    REP(i,n){
        scanf("%d%d",&u,&k);
        REP(j,k){
            scanf("%d%d",&to,&c);
            graph[u].push_back({c,to});
        }
    }
    dijkstra(0);
    REP(i,n){
        printf("%d ",i);
        printf("%d\n",v[i]);
    }
    return 0;
}

C++: // ダイクストラ法
// Dijkstra's Algorithm
// priority_queue
// Single Source Shortest Path 2 単一始点最短経路
#include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <vector>
using namespace std;

static const int MAX = 10000;
static const int INF = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int>> adj[MAX]; //重み付き有向グラフ

void dijkstra() {

    priority_queue<pair<int, int>> PQ;
    int d[MAX], color[MAX];

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

    d[0] = 0;
    PQ.push(make_pair(0, 0));
    color[0] = BLACK;

    while (!PQ.empty()) {
        
        pair<int, int> f = PQ.top();
        PQ.pop();
        int u = f.second;

        color[u] = BLACK;

        // 最小値を取り出し、それが最短でなければ無視
        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;
                // priority_queueのため-1を掛ける
                PQ.push(make_pair(d[v]*(-1), v));
                color[v] = GRAY;
            }
        }
    }

    for(int i = 0; i < n; i++) {
        cout << i << " " << (d[i] == INF ? -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;
}