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++: #define dbg(...) fprintf(stderr,__VA_ARGS__)
#define dpr(x) cerr<<#x<<": "<<x<<endl;
#define dprc(c) do{cerr<<#c<<":";for(auto&_i:(c)){cerr<<" "<<_i;}cerr<<endl;}while(0)
#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
int INF = 1e9+7;
#define all(c) (c).begin(), (c).end()
#define tr(i,c) for(auto i=(c).begin();i!=(c).end();i++)
#define rtr(i,c) for(auto i=(c).rbegin();i!=(c).rend();i++)
#define rep(i,b) for(auto i=0;i<(b);i++)
#define pb push_back
#define sz(c) int((c).size())

int main(int argc, char **argv)
{
  int n;
  scanf("%d", &n);

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

  vi d(n, INF);
  vector<bool> visited(n, false);
  int vc = 0;
  priority_queue<pii, vector<pii>, greater<pii>> q;

  d[0] = 0;
  visited[0] = true;
  vc = 1;
  q.push(pii(0, 0));
  
  while(!q.empty()) {
    pii p = q.top(); q.pop();
    int u = p.second;

    if (d[u] < p.first) continue;

    visited[u] = true;
    for (auto e:G[u]) {
      int v = e.first;
      int c = e.second;
      if (!visited[v] && (d[u] + c < d[v])) {
        d[v] = d[u] + c;
        q.push(pii(d[v], v));
      }
    }
  }

  for (int i = 0; i < n; i++) {
    printf("%d %d\n", i, d[i]);
  }

  return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
static const int MAX = 10000;
static const int INF=(1<<20);
static const int SHIRO=0;
static const int HAI=1;
static const int KURO=2;
int n;
vector<pair<int, int> > adj[MAX];

void dij(){
  priority_queue<pair<int, int> > PQ;
  int color[MAX];
  int d[MAX];
  int i=0;
  int j=0;
  int v;
  for(i=0;i<n;i++){
    d[i]=INF;
    color[i]=SHIRO;
  }
  d[0]=0;
  PQ.push(make_pair(0,0));
  color[0]=HAI;

  while( !PQ.empty()){
    pair<int, int>f=PQ.top();
    PQ.pop();
    int u=f.second;
    color[u]=KURO;
    if(d[u]<f.first*(-1)){
      continue;
    }
    for(j=0;j<adj[u].size();j++){
      v=adj[u][j].first;
      if(color[v]==KURO){
        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]=HAI;
      }
    }
  }
  for(i=0;i<n;i++){
    cout << i << " " << (d[i]==INF ? -1 : d[i])<< endl;
  }
}
int main(){
  int k,u,v,c,i,j;

  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));
    }
  }
  dij();

  return 0;
}

C++: #include <iostream>
#include <queue>
#include <algorithm>
#include <vector>


using namespace std;

using ll = long long;

const ll MAX = 10000;


vector<vector<pair<ll, ll>>> graph;
bool finished[MAX] = {};
ll d[MAX];
ll n;


void dijkstra()
{
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq;
    pq.push(make_pair(0, 0));

    while (!pq.empty()) {
        auto p = pq.top();
        pq.pop();

        if (finished[p.second])
            continue;

        for (auto e : graph[p.second]) {
            if (!finished[e.second]) {
                pq.push(make_pair(p.first + e.first, e.second));
            }
        }
        finished[p.second] = true;
        d[p.second] = p.first;
    }
}


int main()
{
    cin >> n;
    graph.resize(n);
    for (ll i = 0; i < n; i++) {
        ll u, k;
        cin >> u >> k;
        for (ll j = 0; j < k; j++) {
            ll v, c;
            cin >> v >> c;
            graph[u].push_back(make_pair(c, v));
        }
    }

    dijkstra();

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