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 <queue>
#include <algorithm>
#include <vector>
using namespace std;

const int Max = 10000;
const int Infty = (1 << 21);
const int white = 0, gray = 1, black = 2;

int d[Max], color[Max];
int n;

vector<pair<int, int> > adj[Max];

void dijkstra(int s){
    priority_queue<pair<int, int> > PQ;
    for(int i=0; i<n; i++){
        d[i] = Infty;
        color[i] = white;
    }
    d[s] = 0;
    color[s] = gray;
    PQ.push(make_pair(0, 0)); //(d[u], u) u:be adjacent to s

    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 i=0; i<adj[u].size(); i++){
            int v = adj[u][i].first;
            if(color[v] == black) continue;
            if(d[u] + adj[u][i].second < d[v]){
                d[v] = d[u] + adj[u][i].second;
                color[v] = gray;
                PQ.push(make_pair(d[v] * (-1), v));
            }
        }
    }
    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 >> n >> k;
        for(int j=0; j<k; j++){
            cin >> v >> c;
            adj[u].push_back(make_pair(v, c));
        }
    }

    dijkstra(0);

    return 0;
}

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

typedef pair<int, int> P;
const int N = 2e5;
const int INF = 1e9;

struct edge{ int to,cost; };
vector< edge > G[N];
int n;

void dikstra(int s){
  priority_queue<P,vector<P>,greater<P>> que;
  int d[N]; //sからの最短距離
  fill(d,d+N,INF);
  d[s] = 0;
  que.push({0,s}); //{頂点,最短距離}

  while( !que.empty() ){
    P p = que.top(); que.pop();
    int v = p.second;
    if(d[v] < p.first) continue;
    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;
        que.push( {d[e.to],e.to} );
      }
    }
  }

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

signed main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  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;
      G[u].push_back({v,c});
    }
  }
  dikstra(0);

  return 0;
}

C++: #include<iostream>
#include<cstdio>
#define INF 1<<30
#define FinishFunction return 0
#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;
    }
  }
    
  // Ika berumanfo-do 
  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;
  FinishFunction;// return 0
}

C++: #include <cstdio>
#include <vector>
#include <queue>
using namespace std;
const int MAX_V = 1e+4, INF = 1e+9;
struct edge {int to, cost;};
typedef pair<int, int> P;
int n, d[MAX_V]; vector<edge> G[MAX_V];

void dijkstra(int s) {
  fill(d, d+n, INF); d[s] = 0;
  priority_queue<P, vector<P>, greater<P>> q;
  q.push(P(0, s));
  while(!q.empty()) {
    P p = q.top(); q.pop();
    int now = p.second;
    if(d[now] < p.first) continue;
    for(int i = 0; i < G[now].size(); ++i) {
      edge e = G[now][i];
      if(d[e.to] > d[now] + e.cost) {
        d[e.to] = d[now] + e.cost;
        q.push(P(d[e.to], e.to));
      }
    }
  }
}
int main() {
  scanf("%d", &n);
  for(int i = 0, u, k; i < n; ++i) {
    scanf("%d %d", &u, &k);
    for(int j = 0, v, c; j < k; ++j) {
      scanf("%d %d", &v, &c);
      edge e = {v, c};
      G[u].push_back(e);
    }
  }
  dijkstra(0);
  for(int i = 0; i < n; ++i) {
    printf("%d %d\n", i, d[i]);
  }
}

C++: #include<iostream>
#include<queue>
#include<algorithm>
#include<cstring>
 
using namespace std;
 
typedef pair<int,int>pii;
#define INF 0x3f3f3f3f
#define fi first
#define se second
 
int mcos[10005];
vector <pii> G[1000005];
int N;
 
 
void dijkstra(int start){
  priority_queue<pii,vector<pii>,greater<pii> > pq;
 
  pq.push( pii(0,start) );
  memset( mcos,INF,sizeof(mcos));
  mcos[start]=0;
 
   
  while(!pq.empty() ){
    const pii tmp=pq.top();
    pq.pop();
     
    const int now=tmp.se;
     
    if(mcos[now] < tmp.fi) continue;
     
    for(int i=0;i<G[now].size();++i){
      const int newcost = G[now][i].fi + tmp.fi;
      const int next= G[now][i].se;
       
      if(newcost < mcos[next] ){
    mcos[next]=newcost;
    pq.push( pii(newcost,next) );
      }
    }
  }
  return ;
   
}
 
int main (){
  cin>>N;
  int k,u,v,c;
 
  for(int i=0;i<N;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
      G[u].push_back(make_pair(c,v));
    }
  }
  dijkstra(0);
  for(int i=0;i<N;i++){
    cout<<i<<" "<<mcos[i]<<endl;
  }
  return 0;
}