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 _CRT_SECURE_NO_WARNINGS
// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
template<class T> ostream &operator << (ostream &os, const vector<T> &);
template<size_t n, class...T> typename enable_if<(n>=sizeof...(T))>::type _ot(ostream &, const tuple<T...> &){}
template<size_t n, class...T> typename enable_if<(n< sizeof...(T))>::type _ot(ostream &os, const tuple<T...> &t){
    os << (n == 0 ? "" : " ") << get<n>(t); _ot<n+1>(os, t);
}
template<class...T> ostream &operator << (ostream &os, const tuple<T...> &t){
    _ot<0>(os, t); return os;
}
template<class T, class U> ostream & operator << (ostream &os, const pair<T,U> &p){
    return os << "(" << p.first << ", " << p.second << ") ";
}
template<class T> ostream &operator << (ostream &os, const vector<T> &v){
    for(size_t i = 0; i < v.size(); i++) os << v[i] << (i + 1 == v.size() ? "" : ", "); return os;
}
#ifdef DEBUG
#define dump(...) (cerr << #__VA_ARGS__ << " = " << make_tuple(__VA_ARGS__) \
                   << " (L : " << __LINE__ << ")" << endl)
#else
#define dump(...)
#endif
#define all(c) begin(c), end(c)
#define range(i,a,b) for(int i = a; i < (int)(b); i++)
#define rep(i,b) range(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
using ll = long long;
// #define int ll
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int,int>;
void fastios(){ ios_base::sync_with_stdio(0); cin.tie(0); }
int const mod = 1000000007;
auto const inf = numeric_limits<int>::max()/8;

using Weight = int;
using Capacity = int;
struct Edge {
    int src, dst; Weight weight;
    Edge(int s, int d, int w) : src(s), dst(d), weight(w) {}
};
using Edges = vector<Edge>;
using Graph = vector<Edges>;
using Array = vector<Weight>;
using Matrix = vector<Array>;

pair<vector<Weight>, bool> spfa(const Graph &g, int s){
    const Weight inf = numeric_limits<Weight>::max()/4;
    const int n = g.size(); queue<int> q;
    vector<Weight> dist(n, inf); vector<int> inQ(n);
    vector<int> count(n);
    dist[s] = 0; q.emplace(s); inQ[s] = true; ++count[s];
    bool negCycle = false;
    while(q.size()){
        int v = q.front(); q.pop(); inQ[v] = false;
        for(auto &e : g[v]){
            if(dist[v] != inf && dist[e.dst] > dist[v] + e.weight){
                dist[e.dst] = dist[v] + e.weight;
                if(!inQ[e.dst]){
                    q.emplace(e.dst); inQ[e.dst] = true; ++count[e.dst];
                    if(count[e.dst] >= n){ negCycle = true; goto END; }
                }
            }
        }
    }
 END:;
    return make_pair(dist, !negCycle);
}

int main(){
    fastios();
    int n;
    cin >> n;
    Graph g(n);
    rep(i,n){
        int u,k;
        cin >> u >> k;
        rep(j,k){
            int v,c;
            cin >> v >> c;
            g[u].eb(u,v,c);
        }
    }
    auto dist = spfa(g,0);
    rep(i,n){
        cout << i << ' ' << get<0>(dist)[i] << '\n';
    }
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1<<20);

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

void dij(){
  priority_queue<pair<int,int> > PQ;
  int color[MAX], d[MAX], i, j, u, v;
  for(i = 0; i < n; i++){
    d[i] = INFTY;
    color[i] = 0;
  }
  d[0] = 0;
  PQ.push(make_pair(0,0));
  color[0] = 1;

  while(!PQ.empty()){
    pair<int,int> f = PQ.top();
    PQ.pop();
    u = f.second;
    color[u] = 2;

    if(d[u] < f.first * (-1)) continue;
    for(j = 0; j < G[u].size(); j++){
      v = G[u][j].first;
      if(color[v] == 2) continue;
      if(d[v] > d[u] + G[u][j].second){
        d[v] =  d[u] + G[u][j].second;
        PQ.push(make_pair(d[v] * (-1), v));
        color[v] = 1;
      }
    }
  }

  for(i = 0; i < n; i++){
    cout << i << " " << (d[i] == INFTY ? -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;
      G[u].push_back(make_pair(v,c));
    }
  }

  dij();
  return 0;
}

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

const int MAX = 10000;
const int INF = 1e9 + 7;

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

void dijkstra()
{
  int d[MAX], color[MAX];
  priority_queue<pair<int, int> > pq;

  fill(d, d + MAX, INF);
  fill(color, color + MAX, 0);

  d[0] = 0;
  pq.push(make_pair(0, 0));
  color[0] = 1;

  while (!pq.empty()) {
    pair<int, int> f = pq.top();
    pq.pop();
    int u = f.second;
    color[u] = 2;

    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] == 2) 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] = 1;
      }
    }
  }
  
  for (int i = 0; i < n; i++) 
    cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl;
  }
}

signed main()
{
  int u, k, c, v;

  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);
}