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 <stdio.h>
#include <iostream>
#include <vector>
#include <tuple>
using namespace std;

#define NUM 100
#define NIL -1
#define INF 1000000000
#define WHITE 0
#define BLACK 1
int node_num;
vector<tuple<int, int>> G[NUM];
int V[NUM];
int color[NUM];

void init(void){
    scanf("%d", &node_num);

    for(int i = 0; i < node_num; i++){
        int u, k;
        scanf("%d", &u);
        scanf("%d", &k);

        for(int j = 0; j < k; j++){
            int v_, c;
            scanf("%d", &v_);
            scanf("%d", &c);
            G[u].push_back(make_tuple(v_, c));
        }
    }

    for(int i = 0; i < node_num; i++){
        color[i] = WHITE;
        V[i] = INF;
    }
}

void updateAround(int n){
    color[n] = BLACK;
    for(int i = 0; i < G[n].size(); i++){
        V[get<0>(G[n][i])] = min(V[get<0>(G[n][i])], V[n] + get<1>(G[n][i]));
    }

    int min_index = NIL;
    int min_value = INF;
    for(int i = 0; i < node_num; i++){
        if(color[i] == BLACK){
            continue;
        }
        if(V[i] < min_value){
            min_value = V[i];
            min_index = i;
        }
    }
    if(min_index != NIL){
        updateAround(min_index);
    }
}

int main(void){
    init();

    V[0] = 0;
    updateAround(0);

    for(int i = 0; i < node_num; i++){
        printf("%d %d\n", i, V[i]);
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
#define M 1000000007
int main(void)
{
	int n,i,j,u,k,v,c,min,ki;
	int ri[101][101],flg[101];
	int ans[101];
	scanf("%d",&n);
	for(i=0;i<=100;i++) for(j=0;j<=100;j++) ri[i][j]=M;
	for(i=0;i<n;i++){
		scanf("%d %d",&u,&k);
		for(j=0;j<k;j++){
			scanf("%d %d",&v,&c);
			if(ri[i][v]>c){
				ri[i][v]=c;
			}
		}
	}
	for(i=0;i<n;i++) flg[i]=0,ans[i]=M;
	//for(i=0;i<n;i++) for(j=0;j<n;j++) if(ri[i][j]!=M) printf("%d-%d %d\n",i,j,ri[i][j]);
	ans[0]=0;
	for(i=0;i<n;i++){
		min=M;
		for(j=0;j<n;j++){
			if(flg[j]==0&&ans[j]<min){
				min=ans[j];
				ki=j;
			}
		}
		flg[ki]=1;
		for(j=0;j<n;j++){
			if(min+ri[ki][j]<ans[j]){
				ans[j]=min+ri[ki][j];
			}
		}
	}
	//for(i=0;i<n;i++) printf("%d\n",ans[i]);
	for(i=0;i<n;i++) printf("%d %d\n",i,ans[i]);
	return 0;
}

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

typedef long long ll;
#define REP(i, n, m) for(int i = n; i < m; i++)
#define REPR(i, n, m) for(int i = n; i >= m; i--)
#define LREP(i, n, m) for(ll i = n; i < m; i++)
#define LREPR(i, n, m) for(ll i = n; i >= m; i--)

#define P pair<ll, ll>


const ll INF = 1e9 + 1;
const int MOD = 1e9 + 7;



//---functions---//
int gcd(int a, int b){
    if(a < b) swap(a, b);
    return b?gcd(b, a%b):a;
}

int s2i(string num){stringstream ss; ss << num << flush; int n; ss >> n; return n;}
string i2s(int n){stringstream ss; ss << n << flush; return ss.str();}

bool firstCompare(const P& firstElof, const P& secondElof){
    return firstElof.first < secondElof.first;
}
bool secondCompare(const P& firstElof, const P& secondElof){
    return firstElof.second < secondElof.second;
}
//---------------//
//-----class-----//
class UnionFind{
    public:
        vector<ll> par; //parents
        vector<ll> siz; // sizes of set
        vector<ll> rank; // rank of each element 
    UnionFind(ll n): par(n), siz(n, 1LL), rank(n){
        LREP(i, 0, n) par[i] = i;
    }
    //initialization
    /*
    void init(ll n){
        par.assign(n);
        siz.assign(n, 1LL);
        rank.assign(n);
        LREP(i, 0, n) par[i] = i;
    }
    */

    // find the root of x
    ll find(ll x){
        if(par[x] == x) return x;
        else return par[x] = find(par[x]);
    }

    //Unite two set including x or y
    void unite(ll x, ll y){
        x = find(x);
        y = find(y);
        if(x == y) return;
        if(rank[x] < rank[y]){
            par[x] = y;
            siz[y] += siz[x];
        }else{
            par[y] = x;
            siz[x] += siz[y];
            if(rank[x] == rank[y]) rank[x]++;
        }
    }

    //Do x and y belong to the same set?
    bool issame(ll x, ll y){
        return find(x) == find(y);
    }

};

struct edge{ ll to, cost; };
ll n;
int main(){
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    vector<edge> G[n];
    LREP(i, 0, n){
        ll u, k;
        cin >> u >> k;
        LREP(j, 0, k){
            edge e;
            cin >> e.to >> e.cost;
            G[u].push_back(e);
        }
    }
    ll d[n];
    LREP(i, 0, n) d[i] = INF;
    priority_queue<P, vector<P>, greater<P>> q;
    d[0] = 0;
    q.push(P(0, 0));
    while(!q.empty()){
        P p = q.top(); q.pop();
        ll v = p.second;
        if(d[v] < p.first) continue;
        LREP(i, 0, G[v].size()){
            edge e = G[v][i];
            if(d[e.to] > d[v] + e.cost){
                d[e.to] = d[v] + e.cost;
                q.push(P(d[e.to], e.to));
            }
        }
    }
    LREP(v, 0, n){
        cout << v << ' ' << d[v] << '\n';
    }

}