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>
#define int long long

using namespace std;
const int INF = 1e18;

struct edge
{
    int to;
    int cost;
};
using Graph = vector<vector<edge>>;

#define WHITE 0
#define GRAY 1
#define BLACK 2

int n;
Graph G;

void dijkstra(int start)
{
    int seen[10010];
    int dist[10010];

    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    for (int i = 0; i < n; i++)
    {
        seen[i] = (i == start) ? GRAY : WHITE;
        dist[i] = (i == start) ? 0 : INF;
        pq.push(make_pair(dist[i], i));
    }

    while (!pq.empty())
    {
        auto now = pq.top();
        pq.pop();
        int u = now.second;
        int distU = now.first;

        seen[u] = BLACK;

        for (auto ne : G[u])
        {
            int v = ne.to;
            int cv = ne.cost;
            if (dist[u] + cv < dist[v])
            {
                dist[v] = dist[u] + cv;
                pq.push(make_pair(dist[v], v));
                seen[v] = GRAY;
            }
        }
    }

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

void solve()
{

    // remove the bottom 3 lines when you submit this code.
    std::ifstream in("sample.txt");
    std::cin.rdbuf(in.rdbuf());

    cin.tie(0);
    ios::sync_with_stdio(false);

    cin >> n;
    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((edge){v, c});
        }
    }

    dijkstra(0);
}

signed main()
{
    solve();
    return 0;
}

C++: #include<bits/stdc++.h>

using namespace std;

typedef pair<int,int> P;

struct edge
{
    int to,cost;
    edge(int _to=0,int _cost=0)
    {
        to=_to;cost=_cost;
    }
};

int n;
vector<edge> G[10010];

int d[10010];
const int INF=1e9+7;

void dijkstra(int s)
{
    fill(d,d+n,INF);

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

    while(!q.empty())
    {
        P tmp=q.top();q.pop();
        int v=tmp.second;
        if(d[v]<tmp.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;
                q.push(P(d[e.to],e.to));
            }
        }
    }
}

int main()
{

    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    while(cin>>n)
    {
        int a,b,c,dd;
        for(int i=0;i<n;i++)
        {
            G[i].clear();
            cin>>a>>b;
            for(int j=0;j<b;j++)
            {
                cin>>c>>dd;
                G[a].push_back(edge(c,dd));
            }
        }

        dijkstra(0);

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



    return 0;
}