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 <string>
#include <stack>
#include <queue>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <algorithm>

#include <cstdio>

using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define repc(i, s, n) for (int i = (s); i <= (n); i++)
#define rrep(i, n) for (int i = (n) - 1; i >= 0; i--)
#define rrepc(i, s, n) for (int i = (s); i >= (n); i--)
#define print_array(ary, size) cout << ary[0]; rep1(i, 1, size - 1) cout << ' ' << ary[i]; cout << endl;
typedef long long ll;
typedef unsigned long long ull;

vector<pair<int, int> > adj[10000];
int cost[10000];
int done[10000];

void dijkstra()
{
	priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > PQ;
	pair<int, int> next;	/* first: cost, second: index */
	int index;

	cost[0] = 0;
	PQ.push(make_pair(0, 0));

	while (!PQ.empty()) {
		next = PQ.top();
		PQ.pop();

		index = next.second;

		if (done[index] == 1) continue;
		done[index] = 1;

		rep(i, adj[index].size()) {
			if ((done[adj[index][i].second] == 0)
				&& (cost[adj[index][i].second] > cost[index] + adj[index][i].first)) {
				cost[adj[index][i].second] = cost[index] + adj[index][i].first;
				PQ.push(make_pair(cost[adj[index][i].second], adj[index][i].second));
			}
		}
	}
}

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


	cin >> n;
	rep(i, n) {
		cost[i] = 1000000001;
		done[i] = 0;
		cin >> u >> k;
		rep(j, k) {
			cin >> v >> c;
			adj[u].push_back(make_pair(c, v));
		}
	}

	dijkstra();

	rep(i, n) {
		cout << i << ' ' << cost[i] << endl;
	}

	return 0;
}

C++: #include <iostream>
#include <cstring>
#include <algorithm>
#include <queue>
#include <vector>
using namespace std;
#define INF 0x3f3f3f3f
static const int MAXN=10000;
int vis[MAXN+10],d[MAXN+10];
int n;
vector<pair<int,int> >adj[MAXN];
void dijkstra()
{
    priority_queue<pair<int,int> > PQ;
    memset(d,0x3f,sizeof(d));
    memset(vis,0,sizeof(vis));
    d[0]=0;
    PQ.push(make_pair(0,0));
    vis[0]=1;
    while(!PQ.empty())
    {
        pair<int,int> f=PQ.top();
        PQ.pop();
        int u=f.second;
        vis[u]=2;
        if(d[u]<f.first*(-1))
            continue;
        for(int j=0;j<adj[u].size();j++)
        {
            int v=adj[u][j].first;
            if(vis[v]==2)
                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));
                vis[v]=1;
            }
        }
    }
    for(int i=0;i<n;i++)
        cout<<i<<" "<<(d[i]==INF?-1:d[i])<<endl;
}
int main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0),cout.tie(0);
    int u,k,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;
}

C++: #include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>

using namespace std;
using ll = long long int;
#define rep(i,n) for(int i = 0; i < n; i++)
#define FOR(i, a, b)  for(int i = (a); i < (b) ; i++)

#define pb push_back
#define SORT(v,n) sort(v, v+n)
#define ALL(x) (x).begin(),(x).end()
#define debug(x) cerr << #x << ": " << x << '\n'
#define elif else if
#define itn ll
#define int ll
const int INF = 100100100;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
///                →,↑,←,↓,↗,↖,↙,↘
int dx[8] = { 1, 0, -1, 0, 1, -1, -1, 1 };
int dy[8] = { 0, 1, 0, -1, 1, 1, -1, -1 };
typedef vector<vector<int>> vvi;
typedef vector<vector<vector<int>>> vvvi;
int i, j, k;

static const int MAX = 100;
static const int White = 0;
static const int Gray = 1;
static const int Black = 2;

vector<pair<int, int>> adj[MAX];
int n;

void dijkstra() {
	int d[MAX], p[MAX], color[MAX];
	priority_queue<pair<int, int>> PQ;
	rep(i, n) {
		color[i] = White;
		d[i] = INF;
	}
	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;
		rep(j, adj[u].size()) {
			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;
			}
		}
	}
	rep(i, n) {
		cout << i << ' ' << (d[i] == INF ? -1 : d[i]) << '\n';
	}
}

signed main() {
	ios::sync_with_stdio(false);
	cin >> n;
	rep(i, n) {
		int u,k;
		cin >> u >> k;
		rep(j, k) {
			int v, c;
			cin >> v >> c;
			adj[u].pb(make_pair(v, c));
		}
	}
	dijkstra();
	return 0;
}