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>
#define INF 1<<30
#define MAX 1000000
using namespace std;


struct edge {
  int from,to,cost,k;
};

edge es[MAX];



int main(){
  int n,u,k,E,c,v;
  E = 0;
  scanf("%d",&n);

  for(int i=0;i<n;i++){
    scanf("%d %d",&u,&k);
   
    for(int j=0;j<k;j++){
      scanf("%d %d",&v,&c);
      es[E].from = u;
      es[E].to = v;
      es[E++].cost = c;
    }
  }

  
  int d[MAX];
  for(int i=0;i<n;i++)d[i] = INF;
  d[0] = 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;


  }

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

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

#define MAX 10000
#define INF (1<<30)
#define BLACK 0
#define GRAY 1
#define WHITE 2

int n;
vector< pair<int,int> > graph[MAX];

// プロトタイプ宣言
void dijkstra();
// ここまで

int main(){
	int now,k,to,w;
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>now>>k;
		for(int j=0;j<k;j++){
			cin>>to>>w;
			graph[now].push_back( make_pair(to,w) );
		}
	}

	dijkstra();


	return 0;
}

void dijkstra(){
	priority_queue< pair<int,int> > PQ;
	int color[MAX];
	int d[MAX];
	for(int i=0;i<n;i++){
		d[i]=INF;
		color[i]=WHITE;
	}

	d[0]=0;
	PQ.push(make_pair(0,0));		// （重み、ノード番号）
	color[0]=GRAY;


	while(PQ.empty()==false){
		pair<int,int> f=PQ.top();	PQ.pop();
		int from = f.second;
		color[from]=BLACK;

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

		for(pair<int,int> next:graph[from]){
			int to=next.first;
			int w=next.second;
			if(color[to]==BLACK) continue;

			if(d[to]>d[from]+w){
				d[to]=d[from]+w;

				PQ.push( make_pair(d[to]*(-1), to) );
				color[to]=GRAY;
			}
		}
	}
	for(int i=0;i<n;i++){
		cout<<i<<" "<<(d[i]==INF? -1:d[i])<<endl;
	}
}

C++: #include<iostream>
using namespace std;
#include<cstdio>
#include<vector>
#include<utility>
#include<queue>

typedef vector<pair<int, int> > adj;

struct current_cost
{
	int index, cost;
	bool operator < (const current_cost &cur) const
	{
		return cost > cur.cost;
	}
};

current_cost init(int i, int c)
{
	current_cost cur;
	cur.index = i, cur.cost = c;
	return cur;
}

int main()
{
	int i, j, k, n, m, next, cost;
	scanf("%d", &n);
	adj *adlist;
	adlist = new adj [n];

	for(k = 0; k < n; k++){
		scanf("%d %d", &i, &m);
		for(j = 0; j < m; j++){
			scanf("%d %d", &next, &cost);
			adlist[i].push_back(make_pair(next, cost));
		}
	}
	
	int *d;
	d = new int [n];
	d[0] = 0;
	for(i = 1; i < n; i++){
		d[i] = 200000;
	}

	priority_queue<current_cost> C;
	current_cost cur = init(0, 0);
	C.push(cur);

	int size;
	bool *check;
	check = new bool [n];
	for(i = 0; i < n; i++){ check[i] = false; }

	while(!C.empty())
	{
		cur = C.top(); C.pop();
		if(check[cur.index]) continue;
		check[cur.index] = true;

		i = cur.index;
		size = adlist[i].size();
		for(j = 0; j < size; j++){
			k = adlist[i][j].first;
			if(d[i] + adlist[i][j].second < d[k]){
				d[k] = d[i] + adlist[i][j].second;
				C.push(init(k, d[k]));
			}
		}
	};
	for(i = 0; i < n; i++){ printf("%d %d\n", i, d[i]); }

	return 0;
}

C++: #include <iostream>
using namespace std;

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

int n,M[MAX][MAX];

void dijkstra(){
    int minv;
    int d[MAX],color[MAX];
    
    for(int i=0; i<n; i++){
        d[i] = INFTY;
        color[i] = WHITE;
    }
    
    d[0] = 0;
    //color[0] = GRAY;
    while (1) {
        minv = INFTY;
        int u = -1;
        for(int i=0; i<n; i++){
            if(minv > d[i] && color[i] != BLACK){
                u = i;
                minv = d[i];
            }
        }
        if(u==-1) break;
        color[u] = BLACK;
        for(int v=0; v<n; v++){
            if(color[v]!=BLACK && M[u][v]!=INFTY){
                if(d[v] > d[u] + M[u][v]){
                    d[v] = d[u]+M[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }
    for(int i=0; i<n; i++){
        cout << i << " " << d[i] << endl;
    }
}

int main(){
    cin >> n;
    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            M[i][j] = INFTY;
        }
    }
    
    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;
            M[u][v] = c;
        }
    }
    
    dijkstra();
}