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 namespace std;
using ll =long long;

static const int inf = (1<<21);
static const int white = 0;
static const int gray =  1;
static const int black = 2;
#define SORT(a) sort((a).begin(),(a).end())
#define rSORT(a) reverse((a).begin(),(a).end())
#define For(i, a, b)    for(int i = (a) ; i < (b) ; ++i)
#define rep(i, n)       For(i, 0, n)
#define debug(x)  cerr << #x << " = " << (x) << endl;
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
//Write From this Line

int n;
vector<pair<int,int>> adj[10010]; // 重み付き有向グラフのリスト表現


void dijkstra(){
	priority_queue<pair<int, int> > p_que;
	int color[10010];
	int d[10010];
	rep(i, n){
		d[i] = inf;
		color[i] = white;
	}

	d[0] = 0;
	p_que.push(make_pair(0,0));
	color[0] = gray;

	while( !p_que.empty() ){
		pair<int, int> f = p_que.top(); p_que.pop();
		int u = f.second;
		color[u] = black;

		// 最小値を取り出し、それが最短でなければ無視
		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;
				p_que.push(make_pair(d[v] * (-1), v));
				color[v] = gray;
			}
		}
	}
	rep(i, n){
		cout << i << " " << (d[i] == inf ? -1 : d[i]) << endl;
	}
}

int main()
{
	cin >> n;
	rep(i,n){
		int u, k;
		cin >> u >> k;
		rep(j,k){
			int a, b;
			cin >> a >> b;
			adj[u].push_back(make_pair(a,b));
		}
	}
	dijkstra();
	return 0;
}

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

#define rep(i, n) REP(i, 0, n)
#define REP(i, k, n) for(auto i = k; i != n; i++)
#define rrep(i, n) RREP(i, n, 0)
#define RREP(i, n, k) for(auto i = n; i != k; i--)
#define ALL(x) (x).begin(), (x).end()
#define debug(x) cerr << #x << " " << x << endl
#define in(x, data) (data).find(x) != (data).end()

typedef long long ll;
typedef pair<int, int> PRii;

class Node {
public:
    int dist, number;
    Node(int d, int n) {
        dist = d;
        number = n;
    }
};

bool operator < (const Node &l, const Node &r) {
    return l.dist < r.dist
    || (!(r.dist < l.dist) && l.number < r.number);
};

bool operator > (const Node &l, const Node &r) {
    return r < l;
};

class Edge {
public:
    int to, cost;
    Edge(int t, int c) {
        to = t;
        cost = c;
    }
};

int node_n;
vector<vector<Edge>> edge;
vector<int> d;

void cost_initializer(int n) {
    edge = vector<vector<Edge>>(n, vector<Edge>());
}

void dijkstra(int start_p) {
    d = vector<int>(node_n, INT_MAX); d[start_p] = 0;
    vector<int> prev = vector<int>(node_n);

    priority_queue<Node,vector<Node>,greater<Node>> Q;

    for(int i=0; i<node_n; i++) {
        Q.push(Node(d[i],i));
    }

    while(!Q.empty()) {
        Node u = Q.top(); Q.pop();
        if(u.dist > d[u.number]) continue;
        for(int i=0; i<edge[u.number].size(); i++) {
            int alt = d[u.number] + edge[u.number][i].cost;
            int v = edge[u.number][i].to;
            if(d[v] > alt) {
                d[v] = alt;
                prev[v] = u.number;
                Q.push(Node(d[v],v));
            }
        }
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n; cin >> n;
    node_n = n;
    cost_initializer(node_n);

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

    dijkstra(0);
    rep(i,n) cout << i << " " << d[i] << endl;
    return 0;
}