Go: package main

import (
	"fmt"
	"bufio"
	"os"
	"strconv"
	"container/heap"
)

type Node struct {
	Id int
	Dis int
}

type PriorityQueue []*Node

func (pq PriorityQueue) Len() int { return len(pq) }

func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].Dis < pq[j].Dis
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PriorityQueue) Push(x interface{}) {
	*pq = append(*pq, x.(*Node))
}

func (pq *PriorityQueue) Pop() interface{} {
	n := len(*pq)
	pop := (*pq)[n-1]
	*pq = (*pq)[0:n-1]
	return pop
}

func main() {
	var n int
	fmt.Scan(&n)

	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	g := make([][]int, n)
	c := make([][]int, n)
	pq := make(PriorityQueue, 0, n)
	d := make([]int, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		g[u] = make([]int, k)
		c[u] = make([]int, k)
		for j := 0; j < k; j++ {
			sc.Scan()
			g[u][j], _ = strconv.Atoi(sc.Text())
			sc.Scan()
			c[u][j], _ = strconv.Atoi(sc.Text())
		}

		if u == 0 {
			d[u] = 0
		} else {
			d[u] = 1 << 30
		}
		pq.Push(&Node{u, d[u]})
	}
	heap.Init(&pq)

	for pq.Len() > 0 {
		node := heap.Pop(&pq).(*Node)
		for i := 0; i < len(g[node.Id]); i++ {
			nextId := g[node.Id][i]
			nextDis := node.Dis + c[node.Id][i]
			if nextDis < d[nextId] {
				d[nextId] = nextDis
				heap.Push(&pq, &Node{nextId, nextDis})
			}
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		wr.WriteString(strconv.Itoa(i))
		wr.WriteString(" ")
		wr.WriteString(strconv.Itoa(d[i]))
		wr.WriteString("\n")
	}
	wr.Flush()
}

C++: #include <cstdio>
#include <vector>
#include <queue>

int main(void){

	int n, count, next_node, num_neighbors;
	std::vector< std::vector<int> > edges;
	std::vector< std::vector<int> > neighbors;
	std::vector<bool> isUsed;
	std::vector<int> distance;
	std::priority_queue< std::pair<int, int> > distance_heap;
	
	scanf("%d", &n);
	
	edges.resize(n);
	isUsed.resize(n);
	neighbors.resize(n);
	distance.resize(n);
	
	for(int i=0;i<n;i++){
		scanf("%d %d", &next_node, &num_neighbors);
		edges[next_node].resize(num_neighbors);
		neighbors[next_node].resize(num_neighbors);
		for (int j=0;j<num_neighbors;j++){
			scanf("%d %d", &neighbors[next_node][j], &edges[next_node][j]);
		}
		isUsed[next_node]=-false;
		distance[next_node]=300000;
	}
	isUsed[0] = true;
	count=0;
	distance[0] = 0;
	for(int i=0;i<neighbors[0].size();i++){
		distance[neighbors[0][i]] = edges[0][i];
		distance_heap.push(std::make_pair(distance[neighbors[0][i]*-1], edges[0][i]));
	}

	while(!distance_heap.empty()){
		std::pair<int, int> p = distance_heap.top();
		distance_heap.pop();
		next_node = p.second;
		if (isUsed[next_node]) continue;
		isUsed[next_node] = true;
		for(int i=0; i<neighbors[next_node].size();i++){
			int neighbor = neighbors[next_node][i];
			if (!isUsed[neighbor] && distance[neighbor] > distance[next_node] + edges[next_node][i]){
				distance[neighbor] = distance[next_node] + edges[next_node][i];
				distance_heap.push(std::make_pair(distance[neighbor]*-1, neighbor));
			}
		}
	}
	for(int i=0;i<n;i++){
		printf("%d %d\n", i, distance[i]);
	}
	return 0;
}

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

using namespace std;

typedef pair<int,int> PII;
#define INF 1001001001
#define rep(i,n) for(int i=0; i<n; ++i)
#define mp make_pair

struct edge{
    short to;
    short cost;
    edge(short to,short cost):to(to),cost(cost){}
};

int V;
vector<edge> G[10000];
int d[10000];

void dijkstra(int s){
    priority_queue<PII, vector<PII>, greater<PII>> Q;
    fill(d,d+V,INF);
    d[s]=0;
    Q.push(mp(0,s));

    while(!Q.empty()){
        PII p=Q.top();Q.pop();
        int v=p.second;
        if(d[v]<p.first) continue;
        rep(i,G[v].size()){
            edge e=G[v][i];
            if(d[e.to]>d[v]+e.cost){
                d[e.to]=d[v]+e.cost;
                Q.push(mp(d[e.to],e.to));
            }
        }
    }
}
int n;
int main(){
    cin>>V;
    rep(i,V){
        rep(j,V){
            int u,k;
            cin>>u>>k;
            rep(t,k){
                int v, c;
                cin>>v>>c;
                G[u].push_back(edge(v,c));
            }
        }
    }
    dijkstra(0);
    rep(i,V){
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}

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

template<typename T> struct Graph {
  struct Edge { int to; T cost; };
  vector<int> prev;
  vector<vector<Edge>> g;
  Graph(int n) : prev(n, -1), g(n) {}

  void addEdge(int u, int v, T w) {
    g[u].push_back({v, w});
    //g[v].push_back({u, w});
  }
  vector<T> dijkstra(int s) {
    vector<T> dist(g.size(), -1);
    using Node = pair<T, int>;
    priority_queue<Node, vector<Node>, greater<Node>> pq;
    pq.push({dist[s] = 0, s});

    while (!pq.empty()) {
      auto d = pq.top().first;
      auto u = pq.top().second;
      pq.pop();
      if (dist[u] < d) continue;
      for (auto&& v : g[u]) {
        if (dist[v.to] < 0 || dist[v.to] > dist[u] + v.cost) {
          dist[v.to] = dist[u] + v.cost;
          prev[v.to] = u;
          pq.push({dist[v.to], v.to});
        }
      }
    }
    return dist;
  }
  vector<int> getPath(int t) {
    vector<int> path;
    for (; t != -1; t = prev[t]) path.push_back(t);
    reverse(begin(path), end(path));
    return path;
  }
};

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n; cin >> n;
  Graph<int> g(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.addEdge(u, v, c);
    }
  }
  vector<int> d = g.dijkstra(0);
  for (int i = 0; i < n; ++i) {
    cout << i << ' ' << d[i] << endl;
  }
  return 0;
}