Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include <iostream>
#define rep(i,N) for(int i = 0; i<(int)(N); i++)
#define REP(i,k,N) for(int i = k; i<(int)(N); i++)
#define INF 100000+1
using namespace std;
const int MAX_N = 10000010;
bool d[MAX_N];
int main(){
        int n;
        cin >> n;
        int d[100][100];
        rep(i,100) rep(j,100) d[i][j]=INF;
        int u,k,v,c;
        rep(i,n){
                cin >> u >>k;
                rep(j,k){
                        cin >> v >> c;
                        d[u][v] = c;
                }
        }

        int l[n];
        rep(i,n) l[i]=INF;
        l[0]=0;
        bool update = true;
        while(update) {
                update  = false;
                rep(from,n) rep(to,n){
                        if(l[to] > l[from]+d[from][to]) {
                                update = true;
                                l[to] = l[from]+d[from][to];
                        }
                }
        }
        rep(i,n){
                cout << i << " " << l[i] << endl;
        }

        return 0;
}

C++: #include<iostream>
using namespace std;
static const int MAX = 100;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[MAX][MAX];

void dijkstra(){
    int minv;
    int d[MAX], color[MAX];
    
    for ( int i = 0; i < n; i++ ){
        d[i] = INFTY;
        color[i] = WHITE;
    }
    
    d[0] = 0;

}

int main() {
    cin >> n;
    
    for ( int i = 0; i < n; i++ ){
        for ( int j = 0; j < n; j++ ){
            M[i][j] = INFTY;
        }
    }
    
    int k, c, u, v;
    for ( int i = 0; i < n; i++ ){
        cin >> u >> k;
        for ( int j = 0; j < k; i++ ){
            cin >> v >> c;
            M[u][v] = c;
        }
    }
    
    dijkstra();
    
    return 0;
}

C++: #include <iostream>
#include <queue>
#include <utility>
using namespace std;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int>> adj[100];
int *d;

void dijkstra() {
    priority_queue<pair<int, int>> PQ;
    int d[n], color[n];

    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
        color[n] = WHITE;
    }
    d[0] = 0;
    PQ.push(make_pair(0, 0));

    while (!PQ.empty()) {
        pair<int, int> f = PQ.top();
        PQ.pop();

        int u = f.second;
        color[u] = BLACK;

        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[u] + adj[u][j].second < d[v]) {
                d[v] = d[u] + adj[u][j].second;
                PQ.push(make_pair(d[v] * (-1), v));
                color[v] = GRAY;
            }
        }
    }
    
    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i, d[i]);
    }
}

int main() {
    cin >> n;
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int v, c;
            cin >> v >> c;
            adj[u].push_back(make_pair(v, c));
        }
    }

    dijkstra();

    return 0;
}

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];

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;
    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;
	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;
      adj[u].push_back(make_pair(v,c));
    }}
  dijkstra();
  return 0;
}

C++: #include<bits/stdc++.h>
#define REP(i,n) for(long long i=0;i<n;++i)
#define FOR(i,a,b) for(long long i=a;i<b;++i)
#define F first
#define S second
using namespace std;

typedef pair< int,int > point;
vector< point > graph[101];
vector< int > v(101);
int n;
const int INF=1<<30;

void dijkstra(int s){
    priority_queue< point,vector< point >,greater< point > >pq;
    pq.push({0,s});
    fill(v.begin(),v.end(),INF);
    v[s]=0;
    while(!pq.empty()){
        point p=pq.top();
        pq.pop();
        REP(i,graph[p.S].size()){
            int nex=graph[p.S][i].S;
            int cost=p.F+graph[p.S][i].F;
            if(v[nex]>cost){
                v[nex]=cost;
                pq.push({cost,nex});
            }
        }
    }
}

int main(){
    scanf("%d",&n);
    int u,k,to,c;
    REP(i,n){
        scanf("%d%d",&u,&k);
        REP(j,k){
            scanf("%d%d",&to,&c);
            graph[u].push_back({c,to});
        }
    }
    dijkstra(0);
    REP(i,n){
        printf("%d ",i);
        printf("%d\n",v[i]);
    }
    return 0;
}