Go: package main

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

type Item struct {
	value    int // The value of the item; arbitrary.
	priority int // The priority of the item in the queue.
	// The index is needed by update and is maintained by the heap.Interface methods.
	index int // The index of the item in the heap.
}
type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}
func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = i
	pq[j].index = j
}
func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}
func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 // for safety
	*pq = old[0 : n-1]
	return item
}

type Q struct {
	pq *PriorityQueue
	ds map[int]int // It has always same value as pq. For random access.
}

func newQ() *Q {
	pq := new(PriorityQueue)
	heap.Init(pq)
	return &Q{
		pq: pq,
		ds: make(map[int]int),
	}
}
func (q *Q) pop() (u, d int) {
	item := heap.Pop(q.pq).(*Item)
	delete(q.ds, item.value)
	return item.value, item.priority
}
func (q *Q) get(u int) (int, bool) { // returns d
	d, ok := q.ds[u]
	return d, ok
}
func (q *Q) set(u, d int) {
	q.ds[u] = d
	for _, item := range *q.pq {
		if item.value != u {
			continue
		}

		item.priority = d
		heap.Fix(q.pq, item.index)
		return
	}
	heap.Push(q.pq, &Item{
		priority: d,
		value:    u,
	})
}
func (q *Q) len() int {
	return len(q.ds)
}

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := newQ()
	q.set(0, 0)
	visited := make(map[int]struct{})
	out := make([]int, n)

	for q.len() > 0 {
		u, d := q.pop()
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			dd := d + c
			if d, ok := q.get(uu); !ok || d > dd {
				q.set(uu, dd)
			}
		}

		out[u] = d
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

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

#define INF 1000000000
using namespace std;

struct edge {
    int from;
    int to;
    int w;
};
struct node {
    node() : id {-1}, d {INF}, ns {} {};
    node(int i, vector<edge>& vec) : id {i}, d {INF}, ns {vec} {};
    int id;
    int d;
    vector<edge> ns;
};

vector<int> dijkstra(node* graph, int n, int st){
    auto ds = vector<int>(n, INF);
    auto comp = [](node* x, node* y){return x->d < y->d;};
    priority_queue<node*, vector<node*>, decltype(comp)> que(comp);
    node* start = &graph[st];
    start->d = 0;
    que.push(start);
    while(que.size()){
        node* n = que.top();
        que.pop();
        if(n->d < ds[n->id]){
            ds[n->id] = n->d;
            for(auto e : n->ns){
                node* next_n = &graph[e.to];
                next_n->d = min(next_n->d, n->d + e.w);
                que.push(next_n);
            }
        }
    }
    return ds;
}

int main(){
    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);
    int n;
    cin >> n;
    node graph[n];
    for(int i = 0; i < n; ++i){
        int id;
        int m;
        cin >> id >> m;
        auto vec = vector<edge>(m);
        int v, c;
        for(int j = 0; j < m; ++j){
            cin >> v >> c;
            vec[j] = edge {id, v, c};
        }
        graph[id] = node(id, vec);
    }
    auto ds = dijkstra(graph, n, 0);
    for(int i = 0; i < n; ++i){
        cout << i << ' ' << ds[i] << endl;
    }
}

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

struct Edge {
	int to, weight;
};

int main()
{
	int n, u, k, v, c, distance[100]{}, upd_num = 1;
	bool must_update[100]{ 1 };
	std::vector<Edge> dest[100];

	std::cin >> n;
	for (int i = 0; i < n; ++i)
	{
		std::cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			std::cin >> v >> c;
			dest[u].push_back({ v, c });
		}
		if (i)
			distance[i] = 2000000000;
	}

	while (upd_num)
		for (int i = 0; i < n && upd_num; i++)
		{
			if (!must_update[i]) continue;

			must_update[i] = false;
			upd_num--;
			for (auto e : dest[i])
			{
				int tmp = distance[i] + e.weight;
				if (tmp < distance[e.to])
				{
					distance[e.to] = tmp;
					if (!must_update[e.to])
					{
						must_update[e.to] = true;
						upd_num++;
					}
				}
			}
		}

	for (int i = 0; i < n; i++)
	{
		std::cout << i << " " << distance[i] << std::endl;
	}

	return 0;
}

C++: #include<bits/stdc++.h>
#define pb push_back
using namespace std;
long long dis[10002];
bool vis[10002];
vector<int> a[10002];
vector<int> b[10002];
int n,u,k,x,t=1,w,m,s,v;
queue<int> q;
int main(){
	cin>>n;
	memset(vis,false, sizeof(vis));
	memset(dis,0x1f1f1f1f,sizeof(dis));
	for (int i=0; i<n; i++){
		cin>>u>>k;
		while (2*k--){
			  cin>>v>>w;
			  a[u].pb(v);
		      b[u].pb(w);
		}
	}
	q.push(0);
	dis[0]=0;
	while (!q.empty()){
		  x=q.front(); q.pop(); vis[x]=false;
		  for (int i=0; i<a[x].size(); i++){
		  	  if (dis[a[x][i]]>dis[x]+b[x][i]){
		  	  	  dis[a[x][i]]=dis[x]+b[x][i];
		  	  	  if (!vis[a[x][i]]){
		  	  	  	  vis[a[x][i]]=true;
		  	          q.push(a[x][i]);
                  }
			 }
		  	  
		  }
	}
    for (int i=0; i<n; i++){
		cout<<i<<' '<<dis[i]<<'\n';
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> P;
vector<vector<P> > G;
signed main(){
  int n;
  cin>>n;
  int INF=1LL<<55LL;
  G.resize(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[u].push_back(P(v,c));
    }
  }
  int d[n];
  for(int i=0;i<n;i++) d[i]=INF;
  d[0]=0;

  priority_queue<P,vector<P>,greater<P> > q;
  d[0]=0;
  q.push(P(0,0));

  while(!q.empty()){
    P p=q.top();q.pop();
    int u=p.second,c=p.first;
    //cout<<u<<" "<<c<<endl;
    if(d[u]<c) continue;
    for(P e:G[u]){
      int v=e.first,w=e.second;
      if(d[v]>d[u]+w){
	d[v]=d[u]+w;
	q.push(P(d[v],v));
	//cout<<v<<":"<<d[v]<<endl;
      }
    }
  }
  
  for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
  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(void){
  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(void){
  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>f = PQ.top();
    PQ.pop();
    
    u = f.second;
    color[u] = BLACK;

    if(d[u] < f.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;
  }
}