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>
using namespace std;

struct Edge {
  /*
    dst -> destination
    weight -> weight
   */
  int dst,weight;
};

struct Data {

  int place,min;

  bool operator < (const Data& data)const{
    //if( min < data.min ) => true;
    if(data.min != min)return min > data.min;
    return data.place > place;
  }

};

//int cost[100001][100001];
vector<Edge> cost[10001];
int n;
int mindist[10001];
bool used[10001];

void dijkstra(){

  for(int i=0 ; i < 10001 ; i++){
    mindist[i]=1e9;
  }
  
  mindist[0]=0;

  priority_queue<Data> PQ;

  PQ.push((Data){0,0});

  while(!PQ.empty()){
    Data a=PQ.top();
    PQ.pop();
    if( mindist[a.place] < a.min ) continue;
    for(int i=0 ; i < (int)cost[a.place].size() ; i++){
      if(mindist[cost[a.place][i].dst] > cost[a.place][i].weight+mindist[a.place]){
	mindist[cost[a.place][i].dst] = cost[a.place][i].weight+mindist[a.place];
	PQ.push((Data){cost[a.place][i].dst,mindist[cost[a.place][i].dst]});
      }
      //cost[a.place].pop_back();
    } 
  }
  
  for(int i=0 ; i < n ; i++){
    cout <<i<<" "<<mindist[i]<<endl;
  }
  
}
int main(){
  
  int u,k,v,c;
  
  // 0 -> 1 weight : 3
  /*  
      cost[0].push_back((Edge){1,3});
      cost[0].push_back((Edge){0,4});
      cost[2].push_back((Edge){0,3});
  */
  
  cin >>n;
  
  for(int i=0 ; i < n ; i++){
    cin >>u>>k;
    for(int j=0 ; j < k ; j++){
      cin >>v>>c;
      cost[u].push_back((Edge){v,c});
    }
  }

  dijkstra();

  return 0;
}


/*
1sec => 10^8


 */

C++: #include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
const long long INF = 1LL << 60;    // 1.15x10^18
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using edge = pair<int, long long>;
using Graph = vector<vector<edge>>;

vector<long long> dijkstra(const Graph &g, int s) {
    int n = g.size();
    vector<long long> dist(n, INF);
    vector<bool> fixed(n);
    dist[s] = 0;
    while (true) {
        int u = -1;
        for (int i = 0; i < n; i++) if (!fixed[i]) {
            if (u == -1 || dist[i] < dist[u]) u = i;
        }
        if (u == -1) break;
        fixed[u] = true;
        for (auto &e: g[u]) chmin(dist[e.first], dist[u] + e.second);
    }
    return dist;
}

int main() {
    int V; cin >> V;
    Graph g(V);
    for (int i = 0; i < V; i++) {
        int u, k; cin >> u >> k;
        while (k--) {
            int v, c; cin >> v >> c;
            g[u].emplace_back(v, c);
        }
    }
    auto dist = dijkstra(g, 0);
    for (int u = 0; u < V; u++) cout << u << " " << dist[u] << endl;
    return 0;
}

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

static const int INFTY = (1<<21);
enum Color{
    WHITE,
    GRAY,
    BLACK
};
int n;

//int M[100][100];
vector<pair<int,int> > adj[10000];   //隣接リスト
priority_queue<pair<int, int> > PQ; 
Color color[10000];
int d[10000];

void dijkstra(){
    for(int i=0; i<n; i++){
        color[i] = WHITE;
        d[i] = INFTY;
    }
    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, size = adj[u].size(); j<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(){

    cin >> n;
    for(int i=0; i<n; i++){
        int u, k;
        cin >> u >> k;
        for(int j=0; j<k; j++){
        int v, g;
        cin >> v >> g;
        adj[u].push_back(make_pair(v, g));
        }
    }

    dijkstra();
    return 0;
}

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


using namespace std;



int main() {
	int n,tmp1,tmp2,size;
	int cnt_arrived=0;
	pair<int, int> ptmp;
	priority_queue<pair<int, int>,vector<pair<int,int>>,greater<pair<int,int>>> pq;
	cin >> n;
	int** mat = new int* [n];
	vector<pair<int, int>>* list_adjacent = new vector<pair<int, int>>[n];
	int* dist = new int[n];
	for (int i = 0;i < n;i++) {
		cin >> tmp1 >> size;
		for (int j = 0;j < size;j++) {
			cin >> tmp1 >> tmp2;
			list_adjacent[i].push_back(make_pair(tmp1, tmp2));
		}
		dist[i] = -1;
	}
	pq.push(make_pair(0, 0));
	while (cnt_arrived < n) {
		ptmp = pq.top();
		pq.pop();
		if (dist[ptmp.second] == -1) {
			cnt_arrived++;
			dist[ptmp.second] = ptmp.first;
			for (int i = 0;i < list_adjacent[ptmp.second].size();i++) {
				pq.push(make_pair(ptmp.first + list_adjacent[ptmp.second][i].second, list_adjacent[ptmp.second][i].first));
			}
		}
	}
	for (int i = 0;i < n;i++) {
		cout << i << " " << dist[i] << endl;
	}
}