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 <vector>
#include <queue>
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;
vector<pair<int, int> > adj[MAX];
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;
}

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;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
#define N 10000
#define WHITE 0
#define GRAY 1
#define BLACK 2
static const int INFTY = (1<<20);
int n;
vector<pair<int,int> >adj[N];
void dijkstra(void);
int main()
{
  int i,j,k;
  int u, v, c;

  cin >> n;

  for(i = 0;i < n;i++)
  {
    cin >> u >> k;

    for(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 i,j;
  int u,v;
  int d[N],color[N];

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

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

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

    u = a.second;
    color[u] = BLACK;

        if(d[u] < a.first*(-1))
        {
          continue;
        }

        for(j = 0;j < adj[u].size();j++)
        {
          v = adj[u][j].first;

          if(color[v] == BLACK)
          {
    	       continue;
          }

          if(d[v] > d[u] + adj[u][j].second)
          {
    	       color[v] = GRAY;
    	       d[v] = d[u] + adj[u][j].second;
    	       PQ.push(make_pair(d[v]*(-1),v));
          }
        }

      }

      for(i = 0;i < n;i++)
      {
        cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
      }
    }

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,N) for(ll i=0;i<N;++i)
typedef long long int ll;
ll INF = 900010;
static const int white = 0;
static const int gray = 1;
static const int black = 2;
using P = pair<int ,int>;

ll N;
vector<vector<P> > G(10010);

void dijkstra(){
    priority_queue<P, vector<P> , greater<P> > pq;
    vector<int> color(N,white);
    vector<int> d(N,INF);
    d[0] = 0;
    pq.push(make_pair(0,0));
    color[0] = gray;

    while(!pq.empty()){
        P f = pq.top(); pq.pop();
        int u = f.second;
        color[u] = black;

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

        for(auto e : G[u]){
            int v = e.first;
            if( color[v] == black ) continue;
            if(d[v] > d[u] + e.second ){
                d[v] = d[u] + e.second;
                pq.push(make_pair(d[v], v));
                color[v] = gray;
            }
        }
    }

    rep(i,N){
        cout << i << " " << (d[i] == INF ? -1 : d[i] ) << endl;
    }
}

int main(){
    cin >> N;
    rep(j,N){
        ll u,k; cin >> u >> k;
        rep(i,k){
            ll v,c; cin >> v >> c;
            G[u].push_back(make_pair(v,c));
        }
    }

    dijkstra();
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using pii = pair<int, int>;
using vpii = vector<pii>;
using vvpii = vector<vpii>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define WHITE 0
#define VISITED 1
#define CANDIDATE 2

void dks(vvpii &g, vi &d, vi &s) {
  priority_queue<pii, vpii, greater<pii>> q;
  q.push(make_pair(d[0], 0));

  while (!q.empty()) {
    auto qt = q.top(); q.pop();
    int u = qt.second, c = qt.first;
    s[u] = VISITED;

    if (d[u] < c) continue;
    
    for (auto cp: g[u]) {
      int v = cp.first, t = d[u] + cp.second;
      if (s[v] != VISITED && t < d[v]) {
        d[v] = t;
        s[v] = CANDIDATE;
        q.push(make_pair(d[v], v)); 
      }
    }
  }
}

int main() {
  int n;
  cin >> n;
  
  vvpii g(n);
  rep(_, n) {
    int u, k;
    cin >> u >> k;

    rep(__, k) {
      int v, c;
      cin >> v >> c;

      g[u].push_back(make_pair(v, c));
    }
  }
  
  vi d(n, 1 << 21), s(n, WHITE);
  d[0] = 0;
  dks(g, d, s);

  rep(i, n) printf("%d %d\n", i, d[i]);
}