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>
#include <queue>
#include <limits>
using namespace std;

struct vec {
    int t, c;
    vec(int to, int cost):t(to),c(cost){}
    bool operator>(const vec &r)const{return t>r.t;}
};
vector<vec> adj[100];
int d[100];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin>>n;
    for(int i=0; i<n; i++) d[i]=numeric_limits<int>::max();
    for(int i=0; i<n; i++) {
        int u,k;
        cin>>u>>k;
        adj[u].reserve(k);
        for(int j=0; j<k; j++) {
            int v,c;
            cin>>v>>c;
            adj[u].push_back(vec(v,c));
        }
    }
    priority_queue<vec, vector<vec>, greater<vec> >q;
    q.push(vec(0,0));
    while(!q.empty()) {
        vec e=q.top();
        q.pop();
        if(d[e.t]<=e.c) continue;
        d[e.t]=e.c;
        for(vector<vec>::iterator it=adj[e.t].begin(); it!=adj[e.t].end(); ++it) q.push(vec(it->t, e.c+it->c));
    }
    for(int i=0; i<n; i++) cout<<i<<' '<<d[i]<<'\n';
    return 0;
}

C++: //
// Created by tattsun on 2017/02/16.
//

#include <iostream>

#define MAX_N 101
#define NIL -1
#define INFTY 1000000

using namespace std;

enum Status {
    NotVisited,
    Visited,
};

int n;
int w[MAX_N][MAX_N];
Status st[MAX_N];

int min(int x, int y) {
    if(x < y) return x;
    return y;
}

int dfs(int v, int cost, int target) {
    if(v == target) {
        return cost;
    }

    int c = MAX_N * INFTY;

    st[v] = Visited;

    for(int i=0; i<n; i++) {
        int x = w[v][i];
        if(x == INFTY || st[i] == Visited) continue;

        c = min(c, dfs(i, cost+x, target));
    }

    st[v] = NotVisited;

    return c;
}

int solve(int i) {
    return dfs(0, 0, i);
}

int main() {
    for(int i=0; i<MAX_N; i++) {
        st[i] = NotVisited;
        for (int j = 0; j < MAX_N; j++) {
            w[i][j] = INFTY;
        }
    }

    cin >> n;

    int u, k, v, c;
    for(int i=0; i<n; i++) {
        cin >> u >> k;
        for(int j=0; j<k; j++) {
            cin >> v >> c;
            w[u][v] = c;
        }
    }

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

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#define rep(i, n) for (int i = 0; i < n; i++)

using namespace std;
typedef vector<int> vi;
typedef pair<int, int> pii;

const int INF = 1 << 30;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100;

vector<pii> G[N];
int d[N];

int main() {
	int n; cin >> n;
	rep(i, n) {
		int _, n2; cin >> _ >> n2;
		rep(j, n2) {
			int v, c; cin >> v >> c;
			G[i].push_back(pii(c, v));
		}
	}
	rep(i, n) d[i] = INF;

	priority_queue<pii, vector<pii>, greater<pii>> Q;
	d[0] = 0;
	Q.push(pii(0, 0));
	while (!Q.empty()) {
		pii p = Q.top(); Q.pop();
		for (auto i : G[p.second]) {
			if (d[i.second] <= d[p.second] + i.first) continue;
			d[i.second] = d[p.second] + i.first;
			Q.push(i);
		}
	}
	rep(i, n) cout << i << ' ' << d[i] << endl;
}

C++: #include<iostream>
using namespace std;
static const int MAX=100;
static const int INF=(1<<21);
static const int APE=0;
static const int MID=1;
static const int BOT=2;

int n, M[MAX][MAX];

void dijkstra(){
  int mv, i, u, v;
  int d[MAX], c[MAX];

  for(i=0;i<n;i++){
    d[i]=INF;
    c[i]=APE;
  }

  d[0]=0;
  c[0]=MID;
  while(1){
    mv=INF;
    u=-1;
    for(i=0;i<n;i++){
      if(mv>d[i]&&c[i]!=BOT){
        u=i;
        mv=d[i];
      }
    }
    if(u==-1)break;
    c[u]=BOT;
    for(v=0;v<n;v++){
      if(c[v]!=BOT&&M[u][v]!=INF){
        if(d[v]>d[u]+M[u][v]){
          d[v]=d[u]+M[u][v];
          c[v]=MID;
        }
      }
    }
  }
  for(i=0;i<n;i++){
    cout<<i<<" "<<(d[i]==INF ? -1 : d[i])<<endl;
  }
}

int main(){
  int i, j, k, c, u, v;

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

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

  return 0;
}