Go: package main

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

type Node struct {
	Id int
	Dis int
}

type PriorityQueue []*Node

func (pq PriorityQueue) Len() int { return len(pq) }

func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].Dis < pq[j].Dis
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
}

func (pq *PriorityQueue) Push(x interface{}) {
	*pq = append(*pq, x.(*Node))
}

func (pq *PriorityQueue) Pop() interface{} {
	n := len(*pq)
	pop := (*pq)[n-1]
	*pq = (*pq)[0:n-1]
	return pop
}

func main() {
	var n int
	fmt.Scan(&n)

	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	g := make([][]int, n)
	c := make([][]int, n)
	pq := make(PriorityQueue, 0, n)
	d := make([]int, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		g[u] = make([]int, k)
		c[u] = make([]int, k)
		for j := 0; j < k; j++ {
			sc.Scan()
			g[u][j], _ = strconv.Atoi(sc.Text())
			sc.Scan()
			c[u][j], _ = strconv.Atoi(sc.Text())
		}

		if u == 0 {
			d[u] = 0
		} else {
			d[u] = 1 << 30
		}
		pq.Push(&Node{u, d[u]})
	}
	heap.Init(&pq)

	for pq.Len() > 0 {
		node := heap.Pop(&pq).(*Node)
		for i := 0; i < len(g[node.Id]); i++ {
			nextId := g[node.Id][i]
			nextDis := node.Dis + c[node.Id][i]
			if nextDis < d[nextId] {
				d[nextId] = nextDis
				heap.Push(&pq, &Node{nextId, nextDis})
			}
		}
	}

	wr := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		wr.WriteString(strconv.Itoa(i))
		wr.WriteString(" ")
		wr.WriteString(strconv.Itoa(d[i]))
		wr.WriteString("\n")
	}
	wr.Flush()
}

C++: //ALDS1_12_C:Single_Source_Shortest Path II
//C++
#include <iostream>
#include <algorithm>
#include <queue>
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];//加?有向?的?接表表示法
void dijkstra(){
    priority_queue<pair<int,int> > PQ;
    int color[MAX];
    int 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;
        //取出最小?，如果不是最短路径?忽略
        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;
                //priority_queue priority_queue 默??先最大?，因此要乘以-1.
                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;
    }
}
int main(){
    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;//1 此?写成cin>>v>>v; ?了会 
            adj[u].push_back(make_pair(v,c));
        }
    }
    dijkstra();
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <array>
#include <algorithm>
#include <limits>
#include <cmath>
#include <numeric>
#include <string>
#include <queue>

using namespace std;

using ll = long long int;
using ull = unsigned long long int;
#define rep(i, a, b) for(int i = (a); i < (b); ++i )
#define rrep(i, a, b) for(int i = (a); i > (b); --i )
#define REP(i, a, b) for(int i = (a); i <= (b); ++i )
#define RREP(i, a, b) for(int i = (a); i >= (b); --i )
#define llrep(i, a, b) for(ll i = (a); i < (b); ++i )
#define llrrep(i, a, b) for(ll i = (a); i > (b); --i )
#define llREP(i, a, b) for(ll i = (a); i <= (b); ++i )
#define llRREP(i, a, b) for(ll i = (a); i >= (b); --i )
#define ullrep(i, a, b) for(ull i = (a); i < (b); ++i )
#define ullrrep(i, a, b) for(ull i = (a); i > (b); --i )
#define ullREP(i, a, b) for(ull i = (a); i <= (b); ++i )
#define ullRREP(i, a, b) for(ull i = (a); i >= (b); --i )

template<typename T=int>
class UnionFind {
public:
    explicit UnionFind(unsigned long long n) : rank_(n, 0), p_(n, 0) {
        for (T i = 0; i < n; i++) {
            MakeSet(i);
        }
    }

    void MakeSet(T x) {
        p_[x] = x;
        rank_[x] = 0;
    }

    bool Same(T x, T y) {
        return FindSet(x) == FindSet(y);
    }

    void Link(T x, T y) {
        if (rank_[x] > rank_[y]) {
            p_[y] = x;
        } else {
            p_[x] = y;
            if (rank_[x] == rank_[y]) {
                rank_[y]++;
            }
        }
    }

    void Unite(T x, T y) {
        Link(FindSet(x), FindSet(y));
    }

    T FindSet(T x) {
        if (x != p_[x]) {
            p_[x] = FindSet(p_[x]);
        }
        return p_[x];
    }

private:
    std::vector<T> rank_, p_;
};

// 隣接行列を使ったダイクストラ
class Dijkstra {
public:
    Dijkstra(unsigned long long num, int max_cost) :
            num_(num),
            max_cost_(max_cost),
            v_(num, std::vector<int>(num, max_cost)),
            c_(num, 0),
            d_(num, max_cost),
            p_(num, 0) {
    };

    void Compute(int start) {
        d_[start] = 0;
        p_[start] = start;
        while (true) {
            int m = -1;
            int min_d = std::numeric_limits<int>::max();
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (min_d > d_[i])) {
                    min_d = d_[i];
                    m = i;
                }
            }
            if (m < 0) {
                break;
            }
            c_[m] = 1;
            for (int i = 0; i < num_; i++) {
                if ((c_[i] == 0) && (d_[i] > (d_[m] + v_[m][i])) ) {
                    d_[i] = d_[m] + v_[m][i];
                    p_[i] = m;
                }
            }
        }
    }

public:
    int num_;
    int max_cost_;
    std::vector<std::vector<int>> v_;
    std::vector<int> c_;
    std::vector<int> d_;
    std::vector<int> p_;
};

class DijkstraQueue {
public:
    DijkstraQueue(unsigned long long num, int max_cost):
            num_(num),
            adj_(num),
            c_(num, 0),
            d_(num, max_cost),
            p_(num, 0)
    {}

    void Compute(int start) {
        std::priority_queue<std::pair<int, int>> pq;
        d_[start] = 0;
        pq.push(std::make_pair(0, start));
        while (!pq.empty()) {
            auto f = pq.top();// cost, i
            pq.pop();
            int u = f.second;
            c_[u] = 1;
            if (d_[u] < f.first * (-1)) {
                continue;
            }

            for(int j = 0; j < adj_[u].size(); j++) {
                int v = adj_[u][j].first;
                if (c_[v] == 1) 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));
                }
            }
        }
    }
    int num_;
    std::vector<std::vector<std::pair<int, int>>> adj_; //i, cost
    std::vector<int> c_;
    std::vector<int> d_;
    std::vector<int> p_;
};




int N, Q;

int G[100][100];
int d[100];
int p[100];
int c[100];

int main() {
    cin >> N;
//    rep(i, 0, N) {
//        rep(j, 0, N) {
//            G[i][j] = 10000010;
//        }
//    }
//    Dijkstra dj(N, 10000010);
    DijkstraQueue dj(N, 10000010);
    rep(i, 0, N) {
        int u, k;
        cin >> u >> k;
        rep(j, 0, k) {
            int t, d;
            cin >> t >> d;
            dj.adj_[u].push_back(make_pair(t, d));
        }
    }
    dj.Compute(0);
    rep(i, 0, N) {
        cout << i << " " << dj.d_[i] << endl;
    }
}