Go: package main

import (
	"bufio"
	"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
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

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

#define rep(i, n) REP(i, 0, n)
#define REP(i,k,n) for(int i = k; i < n; i++)
#define mmax(start, end) *max_element(start, end)
#define mmin(start, end) *min_element(start, end)
#define argmax max_element
#define argmin min_element
#define push push_back
#define pop pop_back
#define ALL(x) (x).begin(), (x).end()

typedef long long ll;
typedef string str;

int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};

template<class T = ll> T in() {
    T _in;
    cin >> _in;
    return _in;
}

#define EMAX 10000000

int cost[101][101];

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

    ll n=in();
    ll d[101];

    rep(i, n) {
        rep(j, n) {
            cost[i][j] = EMAX;
        }
        d[i] = EMAX;
    }

    rep(i, n) {
        int u=in<int>(), k=in<int>();
        rep(j, k) {
            int v=in<int>(), c=in<int>();
            cost[u][v] = c;
        }
    }

    // ノード0からの距離を調べる
    d[0] = 0;
    bool flag = true;
    while(flag) {
        flag=false;
        // 移動する方法のある全ノードからの，次のノードへの移動コストを考える
        rep(i, n) {
            if(d[i] != EMAX) {
                rep(j, n) {
                    if(i == j)
                        continue;
                    int next_c = d[i] + cost[i][j];

                    // 更新できる場合更新
                    if(d[j] > next_c) {
                        d[j] = next_c;
                        flag=true;
                    }
                }
            }
        }
    }

    rep(i, n) {
        cout << i << " " << d[i] << endl;
        // rep(j, n) {
        //     cout << cost[i][j] << " ";
        // }
        // cout << endl;
    }
    
    return 0;
}

C++: #include<iostream>
#include<vector>
#define N 101
using namespace std;
int n;
vector<int> D(N,1<<30);
//bool visited[N];
vector<bool> visited(N,0);
vector<int> pre(N,0);
vector<vector<int>> M(N,vector<int>(N,0));
//int M[N][N];

void dijkstra(){
    D[0]=0;
    pre[0]=-1;

    while(1){
        int minD=1<<30;
        int u=-1;
        for(int i=0;i<n;i++){
            if(visited[i]) continue;
            if(D[i]<minD){
                u=i;
                minD=D[i];
            }
        }
        if(u==-1) break;

        visited[u]=1;
        for(int i=0;i<n;i++){
            if(visited[i]) continue;
            if(M[u][i]>0 && D[i]>D[u]+M[u][i]){
                D[i]=D[u]+M[u][i];
                pre[i]=u;
            }
        }

    }
}

void init(){
    cin>>n;
    int u,k,c,v;
    for(int i=0;i<n;i++){
        /*for(int j=0;j<n;j++){
            M[i][j]=0;
        }*/
        visited[i]=false;
        cin>>u>>k;
        for(int j=0;j<k;j++){
            cin>>v>>c;
            M[u][v]=c;
        }
    }
}

int main(){
    init();
    /*for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            cout<<M[i][j]<<' ';
        }
        cout<<endl;
    }*/
    dijkstra();
    for(int i=0;i<n;i++){
        cout<<i<<' '<<D[i]<<endl;
    }
    return 0;
}

/*
5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3
*/

C++: #include<stdio.h>
using namespace std;
const int maxn=1<<21;
int n;
int a[105][105];
void dan()
{
    int minx;
    int d[105],color[105];
    for(int i=0;i<n;i++)
    {
        d[i]=maxn;
        color[i]=0;
    }
    d[0]=0;
    while(1)
    {
        minx=maxn;
        int u=-1;
        for(int i=0;i<n;i++)
        {
            if(d[i]<minx&&color[i]!=1)
            {
                minx=d[i];
                u=i;
            }
        }
        if(u==-1) break;
        color[u]=1;
        for(int i=0;i<n;i++)
        {
            if(color[i]==1||a[u][i]==maxn) continue;
            if(d[i]>d[u]+a[u][i])
            {
                d[i]=d[u]+a[u][i];

            }
        }
    }
    for(int i=0;i<n;i++)
    {
        printf("%d ",i);
        printf("%d\n",(d[i]==maxn)?-1:d[i]);
    }
}
int main()
{
    scanf("%d",&n);
    for(int i=0;i<105;i++)
    {
        for(int j=0;j<105;j++)
        {
            a[i][j]=maxn;
        }
    }
    int k,c,u,v;
    for(int i=0;i<n;i++)
    {
        scanf("%d%d",&k,&c);
        for(int j=0;j<c;j++)
        {
            scanf("%d%d",&u,&v);
            a[k][u]=v;
        }
    }
    dan();
    return 0;
}