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 <cstdio>
#include <vector>
#include <queue>
#include <functional>
#include <string.h>

using namespace std;
static const int INF = 2e9;
static const int SIZE = 10001;
typedef pair<int, int> P;
struct edge
{
	int to;
	int cost;
};

int d[SIZE];
vector<edge> G[SIZE];

void solve()
{
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int to, cost;
			scanf("%d %d", &to, &cost);
//			cin >> to >> cost;
			edge e1;
			e1.to = to;
			e1.cost = cost;
			G[u].push_back(e1);
		}
	}
	for (int i = 0; i < SIZE; ++i)
	{
		d[i] = INF;
	}
	d[0] = 0;
	priority_queue<P, vector<P>, greater<P> > pque;
	pque.push(P(0, 0));
	while (!pque.empty())
	{
		P p = pque.top();
		pque.pop();
		int v = p.second;
		for (int i = 0; i < G[v].size(); ++i)
		{
			edge e = G[v][i];
			if (d[e.to] > d[v] + e.cost)
			{
				d[e.to] = d[v] + e.cost;
				pque.push(P(d[e.to], e.to));
			}
		}
	}
	for (int i = 0; i < n; ++i)
	{
		printf("%d %d\n", i, d[i]);
//		cout << i << " " << d[i] << endl;
	}
}

int main()
{
	solve();
	return(0);
}

C++: #include <stdio.h>
#include <iostream>
#include <queue>
using namespace std;

#define NIL -1
#define INF 100000000
#define WHITE 1
#define GREY 2
#define BLACK 3
#define N_MAX 100

int G[N_MAX][N_MAX];
int V[N_MAX];
int V_value[N_MAX];

void init(){
    for(int i = 0; i < N_MAX; i++){
        V[i] = WHITE;
        V_value[i] = INF;
    }

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

int main(void){
    init();
    int n;
    scanf("%d\n", &n);

    for(int i = 0; i < n; i++){
        int u, k;
        scanf("%d %d", &u, &k);
        for(int j = 0; j < k; j++){
            int v, c;
            scanf("%d %d", &v, &c);
            G[u][v] = c;
        }
    }

    priority_queue<pair<int, int>> PQ;

    V[0] = BLACK;
    V_value[0] = 0;
    int new_node = 0;
    
    while(1){
        for(int i = 0; i < n; i++){
            if(G[new_node][i] != NIL && V[i] == WHITE){
                V_value[i] = min(V_value[i], V_value[new_node] + G[new_node][i]);
                PQ.push(make_pair(V_value[i] * (-1), i));
            }
        }

        int min_value;
        int min_index = NIL;
        while(!PQ.empty()){
            pair<int, int> p = PQ.top(); PQ.pop();
            if(p.first * (-1) == V_value[p.second])
                min_value = p.first * (-1);
                min_index = p.second;
                break;
        }

        if(min_index == NIL)
            break;

        new_node = min_index;
        V[new_node] = BLACK;
        V_value[new_node] = min_value;
    }
    
    for(int i = 0; i < n; i++){
        printf("%d %d\n", i, V_value[i]);
    }

    return 0;
}

C++: #include <iostream>
#include <utility>
#include <queue>
#include <limits>

using namespace std;

static const int MAX=10000;
static const int INF=numeric_limits<int>::max();

int n,d[MAX];
vector<pair<int,int> > list[MAX];

void dijkstra(){
  //initialize as min-Heap
  priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > PQ;
  bool visited[n];
  for(int i=0;i<n;i++){
    visited[i]=false;
    d[i]=INF;
  }
  d[0]=0;
  PQ.push(make_pair(0,0));
  while(!PQ.empty()){
    pair<int,int> f=PQ.top(); PQ.pop();
    int u=f.second;
    visited[u]=true;

    //if(d[u]>f.first) continue;

    for(int i=0;i<list[u].size();i++){
      int v=list[u][i].first;
      if(visited[v]==false && d[v]>d[u]+list[u][i].second){
        d[v]=d[u]+list[u][i].second;
        PQ.push(make_pair(d[v],v));
      }
    }
  }
}

int main(){
  cin >> n;
  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;
      list[u].push_back(make_pair(v,c));
    }
  }
  dijkstra();
  for(int i=0;i<n;i++)
    cout << i << " " << d[i] << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const ll INF = 1LL << 60;
const int MAX = 1000000010;
const ll MOD = 1000000007;

int main() {
    int N; cin >> N;
    vector<vector<pair<int, int>>> G(N);
    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[u].push_back(make_pair(v, c));
        }
    }
    vector<int> d(N, MAX);
    vector<bool> checked(N, false);
    priority_queue<pair<int, int>> pq;
    d[0] = 0;
    pq.push(make_pair(0, 0));

    while (!pq.empty()) {
        auto p = pq.top();
        pq.pop();
        int v = p.second;
        
        if (d[v] < p.first * (-1)) continue;
        checked[v] = true;


        for (auto np : G[v]) {
            int nv = np.first;
            if (checked[nv]) continue;

            if (chmin(d[nv], d[v] + np.second)) pq.push(make_pair(d[nv] * (-1), nv));
        }
    }

    for (int v = 0; v < N; v++) {
        cout << v << " " << d[v] << "\n";
    }
    return 0;
}