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>

using namespace std;
typedef pair<int, int> P;

struct edge {
    int t, c;
    edge(int t, int c): t(t), c(c) {}
};

const int INF = 1e9;
int n, u, k, v, c;
vector<edge> G[10000];
int d[10000];

void dijkstra(int s) {
    fill(d, d + n, INF);
    d[s] = 0;

    priority_queue<P, vector<P>, greater<P> > que;
    que.push(P(0, s));
    while (!que.empty()) {
        P p = que.top(); que.pop();
        int v = p.second;
        if (d[v] < p.first) continue;
        for (int i = 0; i < G[v].size(); i++) {
            edge e = G[v][i];
            if (d[e.t] <= d[v] + e.c) continue;
            d[e.t] = d[v] + e.c;
            que.push(P(d[e.t], e.t));
        }
    }
}

int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            cin >> v >> c;
            G[u].push_back(edge(v, c));
        }
    }

    dijkstra(0);

    for (int i = 0; i < n; i++)
        cout << i << " " << d[i] << endl;

    return 0;
}

C++: #include<bits/stdc++.h>
#define range(i,a,b) for(int i = (a); i < (b); i++)
#define rep(i,b) for(int i = 0; i < (b); i++)
#define all(a) (a).begin(), (a).end()
#define show(x)  cerr << #x << " = " << (x) << endl;
const int INF = 1e9;
using namespace std;

struct Edge{
	int to;
	int cost;
	Edge(int to, int cost) : to(to), cost(cost) {}
};

struct Node{
	int dis;
	bool used;
	Node() : dis(INF), used(false) { }
	Node(int d, bool f) : dis(d), used(f) { }
};

typedef vector<vector<Edge>> graph;

int dijkstra(graph g, int s, int n){
	vector<Node> node(n);
	priority_queue<int, vector<pair<int, int>>, greater<pair<int, int>>> q;

	q.push(make_pair(0, s));
	node[s] = Node{0, true};

	while(not q.empty()){
		int dis, pos;
		tie(dis, pos) = q.top(); q.pop();
		node[pos].used = true;

		for(auto e : g[pos]){
			if(node[e.to].used == true) continue;
			if(node[e.to].dis > dis + e.cost){
				node[e.to].dis = dis + e.cost;
				q.emplace(node[e.to].dis, e.to);
			}
		}
	}
	rep(i,n){
		cout << i << ' ' << node[i].dis << endl;;
	}
	return node[0].dis;
}

int main(){
	int n;
	cin >> n;

	vector<vector<Edge>> a(n);
	rep(i,n){
		int from;
		int m;
		cin >> from >> m;
		rep(j,m){
			int to, cost;
			cin >> to >> cost;
			a[from].emplace_back(to, cost);
		}
	}
	dijkstra(a, 0, n);
}

C++: #include<iomanip>
#include<limits>
#include<thread>
#include<utility>
#include<iostream>
#include<string>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<stack>
#include<queue>
#include<cmath>
#include<numeric>
#include<cassert>
#include<random>
#include<chrono>
#include<unordered_set>
#include<unordered_map>
#include<fstream>
#include<list>
#include<functional>
#include<bitset>
#include<complex>
#include<tuple>
using namespace std;
typedef unsigned long long int ull;
typedef long long int ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pi;
typedef pair<double,double> pd;
typedef pair<double,ll> pdl;
#define F first
#define S second
const ll E=1e18+7;
const ll MOD=1000000007;





int main(){
    ll n;
    cin>>n;
    vector<vector<pll>> edge(n);
    for(int i=0;i<n;i++){
        ll u,k;
        cin>>u>>k;
        for(int t=0;t<k;t++){
            ll v,c;
            cin>>v>>c;
            edge[u].push_back({v,c});
        }
    }
    vector<ll> dp(n,E);
    priority_queue<pll,vector<pll>,greater<pll>> Q;
    Q.push({0,0});
    dp[0]=0;
    while(!Q.empty()){
        pll w=Q.top(); Q.pop();
        if(dp[w.S]!=w.F){continue;}
        for(auto &I:edge[w.S]){
            if(dp[I.F]>dp[w.S]+I.S){
                dp[I.F]=dp[w.S]+I.S;
                Q.push({dp[I.F],I.F});
            }
        }
    }
    for(int i=0;i<n;i++){
        cout<<i<<" "<<dp[i]<<endl;
    }
    
    
    return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <map>
using namespace std;
typedef pair<int ,int> P;
struct edge {int to,cost;};
const int INF=1000000000;
int N;
int d[10000];
vector<edge> G[10000];
void dijkstra(int s){
  for(int i=0;i<N;i++)d[i]=INF;
  d[s]=0;
  priority_queue<P,vector<P>,greater<P> > que;
  que.push(P(0,s));
  while(!que.empty()){
    P p=que.top();
    que.pop();
    int v=p.second;
    if(d[v]<p.first)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;
	que.push(P(d[e.to],e.to));
      }
    }
  }
}

int main(){
  scanf("%d",&N);
  for(int i=0;i<N;i++){
    int u,k,c,v;
    scanf("%d %d",&u,&k);
    for(int j=0;j<k;j++){
      scanf("%d %d",&v,&c);
      edge e;e.to=v;e.cost=c;
      G[u].push_back(e);
    }
  }
  dijkstra(0);
  for(int i=0;i<N;i++)printf("%d %d\n",i,d[i]);
  return 0;
}