Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
const INF = 1 << 60

type Edge struct {
	to, cost int
}

type Node struct {
	id, cost int
}

type PQ []Node

func (pq PQ) Len() int           { return len(pq) }
func (pq PQ) Less(i, j int) bool { return pq[i].cost < pq[j].cost }
func (pq PQ) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }

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

func (pq *PQ) Pop() interface{} {
	old := *pq
	n := len(old)
	x := old[n-1]
	*pq = old[0 : n-1]
	return x
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		E[id] = make([]Edge, k)
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id][j] = Edge{to, cost}
		}
	}

	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	done := make([]bool, N)
	pq := &PQ{}
	heap.Init(pq)
	d[0] = 0
	heap.Push(pq, Node{0, 0})
	for pq.Len() > 0 {
		cur := heap.Pop(pq).(Node).id
		if done[cur] {
			continue
		}
		done[cur] = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+d[cur]
			if !done[to] && cost < d[to] {
				d[to] = cost
				heap.Push(pq, Node{to, cost})
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, d[i])
	}
	wtr.Flush()
}

C++: #include <bits/stdc++.h>
using ll = long long;
using namespace std;
#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for(int i = int(a); i < int(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
const long long INFLL = 1LL << 60;
const int INFINT = 1 << 30;
const long long MOD = 1e9 + 7;

template <class T> void vecout(T V) {
    auto t = V.begin();
    while(t != V.end()) {
        cout << " " << *t++;
        // if(t != V.end()) cout << " ";
    }
    cout << endl;
};

struct edge {
    int t;
    int c;
    edge(int a, int b) {
        t = a;
        c = b;
    }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n, u, k, v, c;
    cin >> n;
    vector<edge> E[n];
    rep(i, n) {
        cin >> u >> k;
        rep(j, k) {
            cin >> v >> c;
            edge tmp(v, c);
            E[u].push_back(tmp);
        }
    }

    priority_queue<pair<int, int>, vector<pair<int, int>>,
                   greater<pair<int, int>>>
        Q; // cost,V

    int d[n];
    fill(d, d + n, INFINT);
    Q.push(make_pair(0, 0));

    int fix = 0;
    while(fix < n && !Q.empty()) {
        pair<int, int> v = Q.top();
        Q.pop();
        if(d[v.second] != INFINT) continue;
        d[v.second] = v.first;
        fix++;
        for(auto e : E[v.second]) {
            if(d[e.t] == INFINT) {
                Q.push(make_pair(v.first + e.c, e.t));
            }
        }
    }

    rep(i, n) cout << i << " " << d[i] << "\n";
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
typedef pair<int, long> P;
typedef struct edge{ long cost; int to; }edge;

const long INF = 1e11;

int main(){
  int n; cin >> n;
  long d[n];
  vector<edge> G[n];
  for(int i=0; i<n; i++){
    d[i] = INF;
    int u, k; cin >> u >> k;
    int v, c;
    for(int j=0; j<k; j++){
      cin >> v >> c;
      edge e; e.to = v; e.cost = c;
      G[u].push_back(e);
    }
  }
  priority_queue<P, vector<P>, greater<P>> que;
  d[0] = 0;
  que.push(P(0, 0));
  while(!que.empty()){
    P v = que.top(); que.pop();
    if(d[v.second] < v.first) continue;
    for(int i=0; i<G[v.second].size(); i++){
      edge e = G[v.second][i];
      if(d[e.to] > d[v.second] + e.cost){
        d[e.to] = d[v.second] + e.cost;
        que.push(P(d[e.to], e.to));
      }
    }
  }
  for(int i=0; i<n; i++){
    cout << i << " " << d[i] << endl;
  }
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
static const int MAX = 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[MAX];

void dijkstra()
{
    priority_queue<pair<int, int> > PQ;
    int color[MAX];
    int d[MAX];
    for (int i = 0; i < n; i++)
    {
        d[i] = INFTY;
        color[i] = WHITE;
    }

    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; 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()
{
    int k, u, v, c;

    cin >> n;
    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();

    return 0;
}