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<iostream>
using namespace std;

static const int MAX = 100;
static const int INF = (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 d[MAX], color[MAX];
    int u, minc;

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

    d[0] = 0;

    while(1){
        minc = INF;
        u = -1;
        for(int i = 0; i < n; i++){
            if(color[i] != BLACK && minc > d[i]){
                minc = d[i];
                u = i;
            }
        }

        if(minc == INF) break;

        color[u] = BLACK;

        for(int v = 0; v < n; v++){
            if(M[u][v] != INF && color[v] != BLACK){
                if(d[u] + M[u][v] < d[v]){
                    d[v] = d[u] + M[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }

    for(int i = 0; i < n; i++){
        cout << i << " " << d[i] << endl;
    }
}

int main(){
    cin >> n;

    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            M[i][j] = INF;
        }
    }

    for(int i = 0; i < n; i++){
        int from, k, to, c;
        cin >> from >> k;
        for(int j = 0; j < k; j++){
            cin >> to >> c;
            M[from][to] = c;
        }
    }

    dijkstra();

    return 0;
}

C++: #include<iostream>
#define INF 100000000
#define N 101
#define W 0
#define G 1
#define B 2
using namespace std;
int n,M[N][N],d[N];
void dijkstra(int s){
  int color[N],mincost,p[N],u;
  for(int i=0;i<n;i++) color[i]=W,d[i]=INF;
  d[s]=0;
  p[s]=-1;

  while(1){
    mincost=INF;
     u=-1;    
    for(int i=0;i<n;i++)
      if(color[i]!=B && d[i]<mincost){
	mincost=d[i];
	u=i;
      }
        if(mincost==INF) break;
        color[u]=B;
    for(int i=0;i<n;i++)
      if(color[i]!=B && M[u][i]!=INF)
	if(d[u]+M[u][i]<d[i]){
	  d[i]=d[u]+M[u][i];
	  p[i]=u;
	  color[i]=G;
	}
  }
}
int main(){
  int u,k,c,v;
  cin>>n;
  for(int i=0;i<N;i++) for(int j=0;j<N;j++)M[i][j]=INF;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
    M[u][v]=c;
    }
  }
  dijkstra(0);
  for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
  return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

#define rep(i, n) for(int i = 0; i < n; ++i)
const int max_v = 10100;
const int max_e = 505000;
const int inf = 0x3fffffff;

typedef pair<int, int> P;

typedef struct edge {
    int to, dist;
    edge():to(0),dist(0) {}
    edge(int _to, int _dist):to(_to),dist(_dist) {}
    bool operator < (const edge & o) const {
	return dist > o.dist;
    }
}edge;

struct graph {
    int V, E;
    int d[max_v], prev[max_v];
    bool vis[max_v];
    vector<edge> G[max_v];
    graph():V(0),E(0) {}

    graph(int _V):V(_V),E(0) {}

    graph(int _V, int _E, int ed[][3], bool bidirect):V(_V),E(_E) {
	rep(i, E) {
	    int u = ed[i][0], v = ed[i][1], dist = ed[i][2];
	    G[u].push_back(edge(v, dist));
	    if (bidirect) G[v].push_back(edge(v, dist));
	}
    }
    graph(int _V, int g[][max_v]) {
	V = _V; E = 0;
	rep(i, V) rep(j, V)
	    if (g[i][j] != inf) {
		G[i].push_back(edge(j, g[i][j]));
		++E;
	    }
    }

    void add_edge(int u, int v, int c) {
	G[u].push_back(edge(v, c));
    }

    void output() {
	rep(i, V) {
	    printf("[%d] ", i);
	    rep(j, G[i].size()) {
		printf("(%d %d) ", G[i][j].to, G[i][j].dist);
	    }
	    putchar('\n');
	}
    }

    void dijkstra(int g[][max_v], int s) {
	rep(i, V) d[i] = inf;
	rep(i, V) prev[i] = -1;
	rep(i, V) vis[i] = false;

	d[s] = 0;
	rep(i, V) {
	    int tmp = inf;
	    int u = -1;
	    rep(j, V) {
		if(!vis[j] && d[j] < tmp) {
		    tmp = d[j];
		    u = j;
		}
	    }
	    vis[u] = true;
	    rep(j, V) {
		if(!vis[j] && d[u] + g[u][j] < d[j]) {
		    d[j] = d[u] + g[u][j];
		    prev[j] = u;
		}
	    }
	}
    }

    void dijkstra(int s) {
	rep(i, V) d[i] = inf;
	rep(i, V) prev[i] = -1;
	rep(i, V) vis[i] = false;
	
	priority_queue<edge> pq;
	pq.push(edge(s, 0));
	d[s] = 0;

	while(! pq.empty()) {
	    edge e = pq.top(); pq.pop();
	    if(e.dist > d[e.to]) continue;
	    d[e.to] = e.dist;
	    vis[e.to] = true;
	    
	    rep(j, G[e.to].size()) {
		int v = G[e.to][j].to;
		int dist = G[e.to][j].dist;

		if(!vis[v] && d[e.to] + dist < d[v]) {
		    d[v] = d[e.to] + dist;
		    prev[v] = e.to;
		    pq.push(edge(v, d[v]));
		}
	    }
	}
    }
};

int N, M;

void solve() {
    int u, k, v, c;
    scanf("%d", &N);
    graph g = graph(N);
    rep(i, N) {
	scanf("%d%d", &u, &k);
	rep(j, k) {
	    scanf("%d%d", &v, &c);
	    g.add_edge(u, v, c);
	}
    }
    g.dijkstra(0);
    rep(i, N) {
	printf("%d %d\n", i, g.d[i]);
    }
}

int main() {
    solve();
    return 0;
}