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;
#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define fi first
#define se second
#define mp make_pair
#define itrfor(itr,A) for(auto itr = A.begin(); itr !=A.end();itr++)
#define dame { printf("No\n"); return 0;}
template <class T> using reversed_priority_queue = priority_queue<T, vector<T>, greater<T> >;
typedef long long llong;
char moji[26]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
char moji2[26]={'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};
char moji3[10]={'0','1','2','3','4','5','6','7','8','9'};
#define Sort(a) sort(a.begin(),a.end());
#define Reverse(a) reverse(a.begin(),a.end());
#define print(a) cout << a << endl;
#define MOD llong(1e9+7)
#define MAX int(2 * 1e5 +5)
#define debug(x)  cout << #x << " = " << (x) << endl;
#define pi acos(-1.0)
#define int llong
#define INF llong(1e17)


template <typename T> class Dijkstra{
    vector<pair < T, int >>* edges;
    int* par;
    T* Distance;
    int size;

public:
    Dijkstra(int n){
        size = n;
        edges = new vector<pair<T , int> >[n];
        Distance = new T[n];
        par = new int[n];
    };

    T Get_Distance(int x){
        if(x < 0 or x>= size) return T(-1);
        else return Distance[x];
    };

    void add_edge(T dist, int s,int t);

    void Disp_Graph();

    void Get_Shortest(int s);



};


template<typename T> void Dijkstra<T>::add_edge(T dist, int s,int t){
    edges[s].push_back( mp(dist, t));
}

template<typename T> void Dijkstra<T>::Disp_Graph(){
    REP(i,size){
        REP(j,edges[i].size()){
            cout << edges[i][j].se << " " << edges[i][j].fi <<endl;
        }
        cout << endl;
    }
}


template<typename T> void Dijkstra<T>::Get_Shortest(int s){
    REP(i,size) Distance[i] = T(INF);
    reversed_priority_queue< pair<T, int > > Q;
    bool used[size];
    REP(i,size) used[i] = false;
    REP(i,size) par[i] = -1;
    int Q_size = 1;
    Distance[s] = 0;
    Q.push( mp(T(0),s ) );
    while(Q_size){
        pair < T, int > x = Q.top();
        Q.pop();
        Q_size --;
        if( used[x.se]) continue;
        used[x.se] = true;
        REP(i,edges[x.se].size()){
            pair < T, int > y = edges[x.se][i];
            if(  Distance[y.se] > Distance[x.se] + y.fi){
                Distance[y.se] = Distance[x.se] + y.fi;
                Q.push( mp ( Distance[y.se],y.se) );
                Q_size ++;
                par[y.se] = x.se;
            }
        }

    }

}











signed main(){
    int n,m,s;
    cin >> n;
    Dijkstra<int> D(n);
    int t1,d1;
    REP(i,n){
        int u,k;
        scanf("%lld%lld",&u,&k);
        REP(j,k){
            scanf("%lld%lld",&t1,&d1);
            D.add_edge(d1,u,t1);
        
        }
    }


    D.Get_Shortest(0);
    int tmp = 0;
    REP(i,n){
        printf("%lld %lld\n",i,D.Get_Distance(i));
    }
}