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 <iostream>
# include <algorithm>
# include <queue>
# include <vector>
using namespace std;

static const int MAX = 10000;
static const int INFTY = (1 << 20);
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], 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;
    }
}

void solve() {
    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();
}

int main() {
    // freopen("infile", "r", stdin);
    // freopen("outfile", "w", stdout);
    solve();
    return 0;
}

C++: #include <cstdio>           // printf(), scanf()
#include <vector>
#include <queue>            // priority_queue
#include <algorithm>        // fill()
#include <utility>          // pair

using namespace std;

static const int MAX_V = 10000;
static const int INF = 100000000;

typedef pair<int, int> P;
struct edge
{
	int to;
	int cost;
};

vector<edge> G[MAX_V];
int V;

void
dijkstra()
{
	priority_queue<P, vector<P>, greater<P> > que;
	int d[MAX_V];
	int u;
	unsigned int v; 

	fill(d, d + V, INF);
	d[0] = 0;
	que.push(P(0, 0));

	while (!que.empty())
	{
		P p = que.top(); que.pop();
		int u = p.second;
		if (d[u] < p.first)
			continue;

		for (v = 0; v < G[u].size(); ++v)
		{
			edge e = G[u][v];
			if (d[u] + e.cost < d[e.to])
			{
				d[e.to] = d[u] + e.cost;
				que.push(P(d[e.to], e.to));
			}
		}
	}

	for (u = 0; u < V; ++u)
		printf("%d %d\n", u, d[u]);
}

int
main(int argc, char** argv)
{
	edge e;
	int u, v;
	int c;
	int i, j, k;

	scanf("%d", &V);
	for (i = 0; i < V; ++i)
	{
		scanf("%d %d", &u, &k);
		for (j = 0; j < k; ++j)
		{
			scanf("%d %d", &v, &c);
			e.to = v;
			e.cost = c;
			G[u].push_back(e);
		}
	}

	dijkstra();
	return 0;
}