Go: package main

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

type Item struct {
	value    int // The value of the item; arbitrary.
	priority int // The priority of the item in the queue.
	// The index is needed by update and is maintained by the heap.Interface methods.
	index int // The index of the item in the heap.
}
type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }
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 = i
	pq[j].index = j
}
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
}

type Q struct {
	pq *PriorityQueue
	ds map[int]int // It has always same value as pq. For random access.
}

func newQ() *Q {
	pq := new(PriorityQueue)
	heap.Init(pq)
	return &Q{
		pq: pq,
		ds: make(map[int]int),
	}
}
func (q *Q) pop() (u, d int) {
	item := heap.Pop(q.pq).(*Item)
	delete(q.ds, item.value)
	return item.value, item.priority
}
func (q *Q) get(u int) (int, bool) { // returns d
	d, ok := q.ds[u]
	return d, ok
}
func (q *Q) set(u, d int) {
	q.ds[u] = d
	for _, item := range *q.pq {
		if item.value != u {
			continue
		}

		item.priority = d
		heap.Fix(q.pq, item.index)
		return
	}
	heap.Push(q.pq, &Item{
		priority: d,
		value:    u,
	})
}
func (q *Q) len() int {
	return len(q.ds)
}

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := newQ()
	q.set(0, 0)
	visited := make(map[int]struct{})
	out := make([]int, n)

	for q.len() > 0 {
		u, d := q.pop()
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			dd := d + c
			if d, ok := q.get(uu); !ok || d > dd {
				q.set(uu, dd)
			}
		}

		out[u] = d
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

C++: // http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_12_A
// Graph II - Single Source Shortest Path II
// TODO: REVIEW

#define SUBMIT
//#define DEBUG

#include <utility>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <vector>
#include <limits>
#include <numeric>
#include <functional>
#include <set>
#include <cmath>
#include <cstring>
#include <climits>
#include <memory>
#include <queue>

using namespace std;
using ui64 = unsigned long long;
using i64 = long long;

enum class color_type {
    white,
    gray,
    black
};

const int INF = INT_MAX >> 1;
const ui64 MAX_N = 100000;
vector<pair<int, int>> adj[MAX_N];
int n;

int dijkstra() {
    // (cost, node) pair
    priority_queue<pair<int, int>> pq;
    color_type color[MAX_N];
    int d[MAX_N];

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

    d[0] = 0;
    color[0] = color_type::gray;
    pq.push(make_pair(0, 0));

    while (!pq.empty()) {
        auto f = pq.top();
        pq.pop();
        int u = f.second;
        color[u] = color_type::black;

        // 最小値を取り出してそれが最短でなければ無視
        if (d[u] < -f.first) continue;

        for (int j = 0; j < adj[u].size(); ++j) {
            int v = adj[u][j].first;
            if (color[v] == color_type::black) continue;

            if (adj[u][j].second + d[u] < d[v]) {
                d[v] = d[u] + adj[u][j].second;
                pq.push(make_pair(-d[v], v));
                color[v] = color_type::gray;
            }
        }
    }

    for (int i = 0; i < n; ++i) cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl;
}

int main() {
#ifdef SUBMIT
    auto& stream = cin;
#else
    string program_input_str = R"(5
0 3 2 3 3 1 1 2
1 2 0 2 3 4
2 3 0 3 3 1 4 1
3 4 2 1 0 1 1 4 4 3
4 2 2 1 3 3
)";
    stringstream stream(program_input_str);
#endif
    stream >> n;
    int u, v, c, degree;
    for (int i = 0; i < n; ++i) {
        stream >> u >> degree;
        for (int d = 0; d < degree; ++d) {
            stream >> v >> c;
            adj[u].emplace_back(make_pair(v, c));
        }
    }

#ifdef DEBUG
    for (int y = 0; y < n; ++y) {
        for (int x = 0; x < n; ++x) {
            cout << weight[y][x] << " ";
        }
        cout << endl;
    }
#endif

    dijkstra();
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)   FOR(i,0,n)
#define pb emplace_back
typedef long long ll;
typedef pair<ll,ll> pint;

vector<pint> vp[10001];
ll d[10001];
ll INF=1000100010001000100;
int n;
int dijkstra(int st){
    priority_queue<pint,vector<pint>,greater<pint> > pq;
    rep(i,n) d[i]=INF;
    d[st]=0;
    pq.push(make_pair(0,st));
    while(!pq.empty()){
        pint pi=pq.top();pq.pop();
        int t=pi.second;
        if(d[t]<pi.first) continue;
        for(auto it:vp[t]){
            if(d[it.second]>d[t]+it.first){
                d[it.second]=d[t]+it.first;
                pq.push(make_pair(d[it.second],it.second));
            }
        }
    }
}
int main(){
    cin>>n;
    int u,k,v,c;
    rep(i,n){
        cin>>u>>k;
        rep(j,k){
            cin>>v>>c;
            vp[u].pb(c,v);
        }
    }
    dijkstra(0);
    rep(i,n){
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}

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

const int MAX_V = 10000;
const int INF=1e9;

int cost[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int n;

void dijkstra(int s){
  REP(i,n) d[i]=INF;
  REP(i,n) used[i]=false;
  d[s]=0;
  while(true){
    int v=-1;
    REP(u,n)
      if(!used[u] && (v==-1 || d[u]<d[v]))
	v=u;
    if(v==-1) break;
    used[v]=true;
    REP(u,n) d[u]=min(d[u],d[v]+cost[v][u]);
  }
}

int main(){
  cin>>n;
  REP(i,n)REP(j,n) cost[i][j]=INF;
  REP(i,n){
    int u, k; cin>>u>>k;
    REP(j,k){
      int v,c;
      cin>>v>>c;
      cost[u][v]=c;
    }
  }
  dijkstra(0);
  REP(i,n){
    cout<<i<<" "<<d[i]<<endl;
  }
}