Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

//make priority queue
type Item struct {
	id       int
	priority int // this state is priority and distans from start
	index    int
}

type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }

// we want the ascending-priority-queue.
// So we use less than here.
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}

func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = j
	pq[j].index = i
}

func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}

func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 //for safety
	*pq = old[0 : n-1]
	return item
}

func (pq *PriorityQueue) update(dist int, id int) {
	for _, i := range *pq {
		if i.id == id {
			if i.priority > dist {
				i.priority = dist
			}
		}
	}
}

// the main code
func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())
	return n
}

func dikstra(dist *[][]int, n int) *[]int {
	// preparate priority queue
	inf := 1 << 30
	pq := make(PriorityQueue, n)
	shortests := make([]int, n)
	for i := 0; i < n; i++ {
		pq[i] = &Item{
			id:       i,
			priority: inf,
			index:    i,
		}

		shortests[i] = inf
	}
	pq[0].priority = 0
	shortests[0] = 0
	heap.Init(&pq)

	for pq.Len() > 0 {
		item := heap.Pop(&pq).(*Item)
		shortests[item.id] = item.priority
		for id, d := range (*dist)[item.id] {
			if d != -1 {
				pq.update(item.priority+d, id)
			}
		}
		heap.Init(&pq)
	}
	return &shortests
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	// init
	n := nextInt(sc)
	dist := make([][]int, n)
	for i := 0; i < n; i++ {
		dist[i] = make([]int, n)
		for j := 0; j < n; j++ {
			dist[i][j] = -1
		}
	}

	// std Input
	for i := 0; i < n; i++ {
		u := nextInt(sc)
		k := nextInt(sc)
		for j := 0; j < k; j++ {
			v, c := nextInt(sc), nextInt(sc)
			dist[u][v] = c
		}
	}

	shortests := dikstra(&dist, n)
	for i, d := range *shortests {
		fmt.Printf("%d %d\n", i, d)
	}
}

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

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF (1 << 21)
typedef long long ll;

int main() {
  int n;
  cin >> n;

  vector<int> V[n];
  // int E[n][n];
  map<pair<int, int>, int> E;
  int d[n];
  int visited[n];

  REP(x, n) {
    REP(y, n) {
      // E[x][y] = INF;
      // E[make_pair(x, y)] = INF;
    }
    d[x] = INF;
    visited[x] = 0;
  }

  REP(_, n) {
    int u, k;
    cin >> u >> k;
    REP(__, k) {
      int v, c;
      cin >> v >> c;
      V[u].push_back(v);
      // E[u][v] = c;
      E[make_pair(u, v)] = c;
      // E[v][u] = c;
    }
  }

  d[0] = 0;
  REP(_, n) {
    int minv = -1;
    int mincost = INF;
    REP(v, n) {
      if (!visited[v] && d[v] < mincost) {
        minv = v;
        mincost = d[v];
      }
    }
    visited[minv] = 1;
    for (vector<int>::iterator it = V[minv].begin(); it != V[minv].end(); it++) {
      if (E[make_pair(minv, *it)] < INF && d[minv] + E[make_pair(minv, *it)] < d[*it]) {
        d[*it] = d[minv] + E[make_pair(minv, *it)];
      }
    }
  }

  REP(i, n) {
    cout << i << " " << d[i] << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

const long long INFF = 1e18;

const int MAX_N = 11000;
using TYPE = long long; // ?????¢???????????\??????
vector<pair<int, TYPE> > G[MAX_N];

vector<TYPE> dijkstra(int start){
	vector<TYPE> dist(MAX_N, INFF);
	dist[start] = 0;//dist[i] :=???start->i?????§??????????????¢
	priority_queue<pair<TYPE, int>, vector<pair<TYPE, int> >, greater<pair<TYPE, int> > >  que;
	que.push(make_pair(0, start));
	while(!que.empty()){
		TYPE cost; int u;//????????§???????????£????????? ?????¨?????????
		cost = que.top().first, u = que.top().second;
		que.pop();
		if(dist[u] < cost) continue;
		for (auto tmp : G[u]){
			int v = tmp.first; TYPE time = tmp.second;//??£??\???????????? ?????????????????§????????????
			if(dist[v] > dist[u] + time){//u->v
				// if(dist[v] != INFF) printf("%f %fa\n", dist[v], dist[u] + time);
				dist[v] = dist[u] + time;
				que.push(make_pair(dist[v], v));
			}
		}
	}
	return dist;
}


int main(void) {
	int n; cin >> n;
	rep(q, n) {
		int u, k; cin >> u >> k;
		vector<int> v(k), c(k);
		rep(i, k) cin >> v[i] >> c[i];
		rep(i, k) G[u].push_back(make_pair(v[i], c[i])), G[v[i]].push_back(make_pair(u, c[i]));
	}
	auto dist = dijkstra(0);
	rep(i, n) printf("%d %d\n", i, dist[i]);
	return 0;
}

C++: #include <functional>
#include <queue>
#include <stdio.h>
#include <utility>
#include <vector>

static const int MAX = 10000;
static const int INFINITY = 1 << 20;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;

static int n;
static std::vector<std::pair<int, int> > adj[MAX];

void dijkstra()
{
    std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int> >, std::greater<std::pair<int, int> > > PQ;
    int color[MAX];
    int d[MAX];

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

    d[0] = 0;
    PQ.push(std::make_pair(0, 0));
    color[0] = GRAY;

    while (!PQ.empty()) {
        std::pair<int, int> f = PQ.top();
        PQ.pop();
        int u = f.second;
        color[u] = BLACK;
    
        if (d[u] < f.first)
            continue;

        for (int i = 0; i < adj[u].size(); i++) {
            int v = adj[u][i].first;
            if (color[v] == BLACK)
                continue;
            if (d[v] > d[u] + adj[u][i].second) {
                d[v] = d[u] + adj[u][i].second;
                PQ.push(std::make_pair(d[v], v));
                color[v] = GRAY;
            }
        }
    }

    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i, (d[i] == INFINITY) ? -1 : d[i]);
    }
}

int main()
{
    scanf("%d", &n);
    
    for (int i = 0; i < n; i++) {
        int u, k;
        scanf("%d %d", &u, &k);
        for (int j = 0; j < k; j++) {
            int v, c;
            scanf("%d %d", &v, &c);
            adj[u].push_back(std::make_pair(v, c));
        }
    }
    
    dijkstra();
    return 0;
}