Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	route := make([][]Node, n)
	weight := make([]int, n)
	for i := 0; i < n; i++ {
		weight[i] = NIL
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		route[i] = make([]Node, k)
		for j := 0; j < k; j++ {
			route[u][j] = Node{id: scanInt(), weight: scanInt()}
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for _, nextNode := range route[node.id] {
			if weight[nextNode.id] != NIL {
				continue
			}
			nextNode.weight += node.weight
			heap.Push(h, nextNode)
		}
	}

	for i, w := range weight {
		fmt.Println(i, w)
	}
}

C++: #define _USE_MATH_DEFINES
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <clocale>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

#define IOS ios::sync_with_stdio(false); cin.tie(0);
#define FOR(i, s, n) for(int i = (s), i##_len=(n); i < i##_len; ++i)
#define FORS(i, s, n) for(int i = (s), i##_len=(n); i <= i##_len; ++i)
#define VFOR(i, s, n) for(int i = (s); i < (n); ++i)
#define VFORS(i, s, n) for(int i = (s); i <= (n); ++i)
#define REP(i, n) FOR(i, 0, n)
#define REPS(i, n) FORS(i, 0, n)
#define VREP(i, n) VFOR(i, 0, n)
#define VREPS(i, n) VFORS(i, 0, n)
#define RFOR(i, s, n) for(int i = (s), i##_len=(n); i >= i##_len; --i)
#define RFORS(i, s, n) for(int i = (s), i##_len=(n); i > i##_len; --i)
#define RREP(i, n) RFOR(i, n, 0)
#define RREPS(i, n) RFORS(i, n, 0)
#define ALL(v) (v).begin(), (v).end()
#define SORT(v) sort(ALL(v))
#define RSORT(v) sort(ALL(v), greater<decltype(v[0])>())
#define SZ(x) ((int)(x).size())
#define PB push_back
#define MP make_pair
#define MT make_tuple
#define BIT(n) (1LL<<(n))
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())

using ll = long long;
using Pi_i = pair<int, int>;
using VB = vector<bool>;
using VC = vector<char>;
using VD = vector<double>;
using VI = vector<int>;
using VLL = vector<ll>;
using VS = vector<string>;
using VSH = vector<short>;

const int MOD = 1000000007;
const int INF = 1000000000;
const int NIL = -1;

template<class T, class S>
bool chmax(T &a, const S &b){
    if(a < b){
        a = b; return true;
    }
    return false;
}
template<class T, class S>
bool chmin(T &a, const S &b){
    if(b < a){
        a = b; return true;
    }
    return false;
}


struct edge{
    int to, cost;
    edge(int To, int Cost): to(To), cost(Cost){};
};


int V; //頂点数
vector<vector<edge>> G;
vector<int> d; //sからの距離

void dijkstra(int s){
    //Pi_i first: 距離　second: 頂点
    priority_queue<Pi_i, vector<Pi_i>, greater<Pi_i>> que;
    d.resize(V, INF);
    d[s] = 0;
    que.push(MP(0, s));

    while(!que.empty()){
        Pi_i p = que.top(); que.pop();
        int v = p.second;
        if(d[v] < p.first) continue;
        for(edge &e: G[v]){
            if(d[e.to] > d[v] + e.cost){
                d[e.to] = d[v] + e.cost;
                que.push(MP(d[e.to], e.to));
            }
        }
    }
}

int main(){
    cin >> V;
    G.resize(V);
    REP(i, V){
        int u, k; cin >> u >> k;
        REP(j, k){
            int v, c; cin >> v >> c;
            G[u].PB(edge(v, c));
        }
    }
    dijkstra(0);
    REP(i, V){
        cout << i << " " << d[i] << "\n";
    }
    return 0;
}

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

const int NOTV = 0;
const int VIST = 1;
const int NMAX = 10000;
//const int VMAX = 2000;
const int NILL = -1;
const int INF = 1 << 21;
//int a[NMAX][NMAX];  //??£??\??????
int n;
vector<pair<int, int> > adj[NMAX];

void dijkstra() {
	int d[NMAX];
	int vst[NMAX];
	priority_queue<pair<int, int>> pq;
	for (int i = 0; i < n; i++) {
		vst[i] = NOTV;
		d[i] = INF;
	}
	d[0] = 0;
	pq.push(make_pair(d[0], 0));
	while (not pq.empty()) {
		pair<int, int> f = pq.top(); pq.pop();
		int u = f.second;
		vst[u] = VIST;
		if (d[u] < f.first*(-1)) continue;
		for (int i = 0; i < adj[u].size(); i++) {
			int v = adj[u][i].first;
			if (vst[v] == NOTV) {
				if (d[u] + adj[u][i].second < d[v]) {
					d[v] = d[u] + adj[u][i].second;
					pq.push(make_pair(d[v] * (-1), v));
				}
			}
		}
	}
	for (int i = 0; i < n; i++) {
		cout << i << ' ' << d[i] << endl;
	}
}

int main() {
	cin >> n;
	int k, u, v, c;
	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 <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int,int>;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define INF 1000000000
static const int MAX=10004;
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int n;
vector<P> adj[MAX];

void dijkstra(){
    priority_queue<P> PQ;
    int color[MAX];
    int d[MAX];
    rep(i,n){
        d[i] = INF;
        color[i] = WHITE;
    }
    d[0] = 0;
    PQ.push(make_pair(0,0));
    color[0] = GRAY;

    while (!PQ.empty()){
        P 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]) << endl;
}
int main() {
    int k,u,v,c;
    cin >> n;
    rep(i,n){
        cin >> u >> k;
        rep(j,k){
            cin >> v >> c;
            adj[u].push_back(make_pair(v,c));
        }
    }
    dijkstra();
    
    return 0;
}