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<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(void);

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;

}
      
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;
  }
}

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

struct Edge{
    int from,to;
    Weight weight;
};
using Edges=vector<Edge>;
using Graph=vector<Edges>;

Weight INF=1e9+7;
vector<Weight> Dijkstra(int s,const Graph& g){
    int n=g.size();
    vector<Weight> res(n,INF);
    vector<int> used(n,0);
    res[s]=0;
    priority_queue<pair<Weight,int>,vector<pair<Weight,int>>,greater<>> que;
    que.push({Weight(0),s});
    while(!que.empty()){
        auto p=que.top(); que.pop();
        Weight dist=p.first;
        int v=p.second;
        if(used[v]) continue;
        used[v]=true;
        for(int i=0;i<g[v].size();i++){
            int tdist=dist+g[v][i].weight;
            if(tdist<res[g[v][i].to]){
                res[g[v][i].to]=tdist;
                que.push({tdist,g[v][i].to});
            }
        }
    }
    return res;
}

int main(){
    int n;
    cin>>n;
    Graph g(n);
    for(int i=0;i<n;i++){
        int u,k;
        cin>>u>>k;
        for(int j=0;j<k;j++){
            Edge e;
            e.from=u;
            cin>>e.to>>e.weight;
            g[u].push_back(e);
        }
    }
    auto d=Dijkstra(0,g);
    for(int i=0;i<n;i++){
        cout<<i<<" "<<d[i]<<endl;
    }

    return 0;
}

C++: #include<iostream>
int main(){
  int u,k,C,V,A[1000][1000],D[1000][1000],n;
  std::cin >> n;
  for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = 200001;
  for(int i=0;i<n;i++){ 
    std::cin >> u >> k;
    for(int j=0;j<k;j++){
      std::cin >> V >> C;
      D[u][V] = C;
    } 
  }
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= std::min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)std::cout << i << " " << D[0][i] << std::endl;
  return 0;
}

C++: #include<map>
#include<vector>
#include<cstdio>
using namespace std;
int n,N,i,j,k,c,m;
int main(){
	scanf("%d",&N);
	vector<map<int,int>>dist(N);
	vector<bool>used(N);
	vector<int>cost(N);
	for(;n<N;n++){
		cost[n]=1e9;
		for(scanf("%d%d",&i,&k);k--;dist[i][j]=c)scanf("%d%d",&j,&c);
	}
	for(cost[0]=0;;){
		m=1e9;
		for(i=0;i<N;i++)if(!used[i]&&m>cost[i])m=cost[i];
		if(m==1e9)break;
		for(j=0;j<N;j++)if(m==cost[j]){
			map<int,int>::iterator it=dist[j].begin();
			for(used[j]=1;it!=dist[j].end();it++)if(cost[it->first]>it->second+cost[j])cost[it->first]=it->second+cost[j];
		}
	}
	for(i=0;i<n;i++)printf("%d %d\n",i,cost[i]);
}

C++: #include <bits/stdc++.h>

using namespace std;
using ll =long long;

static const int inf = (1<<21);
static const int white = 0;
static const int gray =  1;
static const int black = 2;
#define SORT(a) sort((a).begin(),(a).end())
#define rSORT(a) reverse((a).begin(),(a).end())
#define For(i, a, b)    for(int i = (a) ; i < (b) ; ++i)
#define rep(i, n)       For(i, 0, n)
#define debug(x)  cerr << #x << " = " << (x) << endl;
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
//Write From this Line

int n;
vector<pair<int,int>> adj[10010]; // 重み付き有向グラフのリスト表現


void dijkstra(){
	priority_queue<pair<int, int> > p_que;
	int color[10010];
	int d[10010];
	rep(i, n){
		d[i] = inf;
		color[i] = white;
	}

	d[0] = 0;
	p_que.push(make_pair(0,0));
	color[0] = gray;

	while( !p_que.empty() ){
		pair<int, int> f = p_que.top(); p_que.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;
				p_que.push(make_pair(d[v] * (-1), v));
				color[v] = gray;
			}
		}
	}
	rep(i, n){
		cout << i << " " << (d[i] == inf ? -1 : d[i]) << endl;
	}
}

int main()
{
	cin >> n;
	rep(i,n){
		int u, k;
		cin >> u >> k;
		rep(j,k){
			int a, b;
			cin >> a >> b;
			adj[u].push_back(make_pair(a,b));
		}
	}
	dijkstra();
	return 0;
}