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 <cstdint>
#include <queue>
#include <vector>

#include <criterion/criterion.h>

using namespace std;

#define GRAPH_SIZE 10000
#define WEIGHT_MAX UINT32_MAX

enum state_t { WHITE, GRAY, BLACK };

static state_t state[GRAPH_SIZE];
static priority_queue<pair<uint32_t, uint32_t>, vector<pair<uint32_t, uint32_t>>, greater<pair<uint32_t, uint32_t>>> min_queue;
static vector<pair<uint32_t, uint32_t>> graph[GRAPH_SIZE];
static uint32_t dist[GRAPH_SIZE];

void single_source_shortest_path(size_t num)
{
  for (uint32_t i = 0; i < num; i++) {
    // dist[i] = WEIGHT_MAX;
    state[i] = WHITE;
  }

  state[0] = GRAY;
  min_queue.push(make_pair(0, 0));

  while (!min_queue.empty()) {
    pair<uint32_t, uint32_t> vertex = min_queue.top();
    min_queue.pop();
    if (state[vertex.first] != BLACK) {
      state[vertex.first] = BLACK;
      dist[vertex.first] = vertex.first;

      for (uint32_t i = 0; i < graph[vertex.first].size(); i++) {
        pair<uint32_t, uint32_t> to = graph[vertex.first][i];
        if (state[vertex.first] != BLACK) {
          min_queue.push(make_pair(vertex.first, vertex.second + to.second));
          state[vertex.first] = GRAY;
        }
      }
    }
  }
}

#include <iostream>

int32_t main()
{
  uint32_t num;
  cin >> num;

  for (uint32_t i = 0; i < num; i++) {
    uint32_t index, len;
    cin >> index >> len;
    for (uint32_t j = 0; j < len; j++) {
      uint32_t connect, weight;
      graph[index].push_back(make_pair(connect, weight));
    }
  }

  single_source_shortest_path(num);

  for (uint32_t i = 0; i < num; i++) {
    cout << i << " " << dist[i] << endl;
  }

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using msi = map<string, int>;
using mii = map<int, int>;
using psi = pair<string, int>;
using pii = pair<int, int>;
using vlai = valarray<int>;
#define rep(i,n) for(int i=0;i<n;i++)
#define range(i,s,n) for(int i=s;i<n;i++)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fs first
#define sc second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define INF 1E9
#define EPS 1E-9
#define MOD (ll)(1E9+7)
#define PI 3.1415926535897932384

template <class T>ostream &operator<<(std::ostream &o, const vector<T> &v)
{
	rep(i, v.size()) {
		o << (i > 0 ? " " : "") << v[i];
	}
	return o;
}

#define MAX_V 100

struct edge {
	edge(int a, int b) {
		cost = a;
		to = b;
	}
	int cost;
	int to;
};

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

void dijkstra(int s) {
	priority_queue<pii, vector<pii>, greater<pii>> que;
	d[s] = 0;
	que.push(pii(0, s));

	while (!que.empty()) {
		pii 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(pii(d[e.to], e.to));
			}
		}
	}

}

int main() {
	int n,u,k,tmpp,tmpw;
	cin >> n;
	d = vector<int>(n, INF);
	G = vector<vector<edge>>(n);
	rep (i,n) {
		cin >> u >> k;
		rep(j, k) {
			cin >> tmpp>>tmpw;
			G[u].emplace_back(tmpw, tmpp);
		}
	}
	dijkstra(0);
	rep(i, n) {
		cout << i << " " << d[i] << endl;
	}
}

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

#define rep(i, n) REP(i, 0, n)
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for (int i = x; i < n; i++)
#define OP(m) cout << m << endl
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> P;

int main()
{
    int n;
    cin >> n;
    vector<P> m[n];

    rep(i, n)
    {
        int u, k;
        cin >> u >> k;
        rep(i, k)
        {
            int v, c;
            cin >> v >> c;
            m[u].push_back(make_pair(v, c));
        }
    }

    priority_queue<P, vector<P>, greater<P>> pq;
    int d[n];
    rep(i, n) d[i] = INT_MAX;
    d[0] = 0;
    pq.push(make_pair(0, 0));
    while (!pq.empty())
    {
        P p = pq.top();
        pq.pop();
        int u = p.second;
        if (d[u] < p.first)
            continue;
        rep(j, m[u].size())
        {
            int v = m[u][j].first;
            if (d[v] > d[u] + m[u][j].second)
            {
                d[v] = d[u] + m[u][j].second;
                pq.push(make_pair(d[v], v));
            }
        }
    }

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

    return 0;
}