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 <bits/stdc++.h>
#define ll long long int
#define P pair<int,int>
struct edge{int to,cost;};
using namespace std;


class CompareDist
{
public:
    bool operator()(pair<int,int> n1,pair<int,int> n2) {
        return n1.second>n2.second;
    }
};

int V;
vector<vector<edge>> G;
vector<int> d;

void dijkstra(int s){
    priority_queue<P,vector<P>,CompareDist> q;
    //fill(d,d+V,INT_MAX);
    d=vector<int>(V,INT_MAX);
    d[s]=0;
    q.push(P(0,s));
    
    while(!q.empty()){
        P p=q.top();q.pop();
        int v=p.first;
        if(d[v]<p.second)continue;
        for(int i=0;i<G[v].size();i++){
            edge e=G[v][i];
            if(d[e.to]>d[v]+e.cost){
                d[e.to]=d[v]+e.cost;
                q.push(P(e.to,d[e.to]));
            }
        }
    }
}
int main(void){
    int n,in,t,c;
    cin>>n;
    V=n;
    G.resize(n);
    d.resize(n);
    for(int i=0;i<n;i++){
        cin>>in;
        int node=in;
        cin>>in;
        for(int j=0;j<in;j++){
            cin>>t>>c;
            G[node].emplace_back((edge){t,c});
        }
        
    }
    dijkstra(0);
    for(int i=0;i<d.size();i++){
        cout<<i<<" "<<d[i]<<endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

const long long INFF = 1e18;

const int MAX_N = 11000;
using TYPE = long long; // ?????¢???????????\??????
vector<pair<int, TYPE> > G[MAX_N];

vector<TYPE> dijkstra(int start){
	vector<TYPE> dist(MAX_N, INFF);
	dist[start] = 0;//dist[i] :=???start->i?????§??????????????¢
	priority_queue<pair<TYPE, int>, vector<pair<TYPE, int> >, greater<pair<TYPE, int> > >  que;
	que.push(make_pair(0, start));
	while(!que.empty()){
		TYPE cost; int u;//????????§???????????£????????? ?????¨?????????
		cost = que.top().first, u = que.top().second;
		que.pop();
		if(dist[u] < cost) continue;
		dist[u] = cost;
		for (auto tmp : G[u]){
			int v = tmp.first; TYPE time = tmp.second;//??£??\???????????? ?????????????????§????????????
			if(dist[v] > dist[u] + time){//u->v
				// if(dist[v] != INFF) printf("%f %fa\n", dist[v], dist[u] + time);
				// dist[v] = dist[u] + time;
				que.push(make_pair(dist[u] + time, v));
			}
		}
	}
	return dist;
}


int main(void) {
	int n; cin >> n;
	rep(q, n) {
		int u, k; cin >> u >> k;
		vector<int> v(k); vector<long long> c(k);
		rep(i, k) cin >> v[i] >> c[i];
		rep(i, k) G[u].push_back(make_pair(v[i], c[i]));
	}
	auto dist = dijkstra(0);
	rep(i, n) printf("%d %d\n", i, dist[i]);
	return 0;
}

C++: #include <iostream>
#include <queue>
#include <algorithm>
#include <vector>
#include <climits>
#define int long long
using namespace std;
typedef pair <int,int> P;
#define to first
#define co second
#define fi first
#define se second
const int INF=INT_MAX;
const int MAX_V=100000;
vector <P> G[MAX_V];
int v,d[MAX_V];

void dijk(int s){
  priority_queue <P,vector<P>,greater<P> > que;
  fill(d,d+v,INF);
  d[s]=0;
  que.push(P(0,s));
  for(;!que.empty();){
    P p=que.top(); que.pop();
    int v=p.se;
    if (d[v]<p.fi) continue;
    for(int i=0;i<(int)G[v].size();i++){
      P e=G[v][i];
      if(d[e.to]>d[v]+e.co){
        d[e.to]=d[v]+e.co;
        que.push(P(d[e.to],e.to));
      }
    }
  }
}
signed main(){
  cin>>v;
  for(int i=0,u,k;i<v&&cin>>u>>k;i++) for(int j=0,a,b;j<k&&cin>>a>>b;j++) G[u].push_back(P(a,b));
  dijk(0);
  for(int i=0;i<v;i++) cout<<i<<" "<<d[i]<<endl;
  return 0;

}

C++: #include<iostream>
#include<algorithm>
#include<queue>
#include<vector>
using namespace std;
static const int N = 10000;
static const int INFTY = (1<<21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

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

void dijkstra(int s){
	priority_queue<pair<int,int>> PQ;
	int color[N];
	int d[N];
	for(int i=0;i<n;i++){
		color[i] = WHITE;
		d[i] = INFTY;
	}
	d[s] = 0;
	PQ.push(make_pair(s,0));
	color[s] = 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;j<adj[u].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;
	int u,k,v,c;
	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(0);
	return 0;
}

C++: #include<iostream>
#include<climits>
#include<cstdio>
using namespace std;

typedef struct{
  int A[10001];
  int ans;
}node;
node T[10001];
int head=0;
int tail=1;
int n;

void function(int num){
  int *Q=new int[1000000];
  Q[0]=0;
  while(true){
    if(head==tail)break;
    num=Q[head++];
        if(head==999999)head=1;
    for(int i=0;i<n;i++){
      if(T[num].A[i]!=-1){
	if(T[i].ans>T[num].ans+T[num].A[i]){
	  T[i].ans=T[num].ans+T[num].A[i];
	  Q[tail++]=i;
	  	  if(tail==999999)tail=1;
	}
      }
    }
  }
  delete [] Q;
}

int main(){
  int num,son,z,w;
  cin>>n;
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      T[i].A[j]=-1;
    }
  }


  for(int i=0;i<n;i++){
    scanf("%d%d",&num,&son);
    T[num].ans=INT_MAX;
    for(int j=0;j<son;j++){
      scanf("%d%d",&z,&w);
      T[num].A[z]=w;
      }
  }

  T[0].ans=0;
  function(0);
 
  for(int i=0;i<n;i++){
      cout<<i<<" "<<T[i].ans<<endl;
  }
  return 0;
}