Go: package main

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

const BIG_COST = 200000

type Path struct {
	node int
	cost int
}

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

	nNodes := scanInt(sc)

	// 各頂点につながる頂点一覧を得るための隣接リスト
	graph := make([][]Path, nNodes)

	for i := 0; i < nNodes; i++ {
		u := scanInt(sc)
		k := scanInt(sc)
		graph[i] = make([]Path, k)
		for d := 0; d < k; d++ {
			graph[u][d] = Path{
				node: scanInt(sc),
				cost: scanInt(sc),
			}
		}
	}

	// 0 から各頂点への最小コストを保存する配列
	minCosts := make([]int, nNodes)

	minCosts[0] = 0
	for i := 1; i < nNodes; i++ {
		minCosts[i] = BIG_COST
	}

	// 各頂点が調査済みかどうかを保持する配列
	checked := make([]bool, nNodes)

	// 最小コストのパスを高速に取得するためのヒープ。
	// コストが小さいものほどルートに来るようにする。
	heap := NewHeap(func(a, b Path) bool {
		return a.cost < b.cost
	})

	heap.insert(Path{node: 0, cost: 0})
	for heap.size > 0 {
		u := heap.extractMax()

		// 隣接行列を使っていた時とは違い、ヒープには
		// 同じノードへのパスが複数含まれうる。そのため既によりコストの低い
		// パスが見つかっている場合は無視する。
		if minCosts[u.node] < u.cost {
			continue
		}

		checked[u.node] = true

		for _, v := range graph[u.node] {
			cost := v.cost + u.cost
			if !checked[v.node] && cost < minCosts[v.node] {
				minCosts[v.node] = cost
				heap.insert(Path{node: v.node, cost: cost})
			}
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i, cost := range minCosts {
		fmt.Fprintf(w, "%d %d\n", i, cost)
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

// --- From ALDS1_9_C: Priority Queue

type Heap struct {
	size   int
	heap   []Path
	isHigh func(a, b Path) bool
}

func NewHeap(isHigh func(a, b Path) bool) Heap {
	heap := make([]Path, 1) // 先頭は不使用
	return Heap{size: 0, heap: heap, isHigh: isHigh}
}

func (h *Heap) insert(v Path) {
	h.size += 1
	if h.size > len(h.heap)-1 {
		h.heap = append(h.heap, v)
	} else {
		h.heap[h.size] = v
	}

	for i := h.size; i > 1; {
		parent := i / 2
		if h.isHigh(h.heap[parent], h.heap[i]) {
			break
		}
		h.heap[i], h.heap[parent] = h.heap[parent], h.heap[i]
		i = parent
	}
}

func (h *Heap) extractMax() Path {
	if h.size <= 0 {
		panic("cannot extract from empty heap")
	}

	max := h.heap[1]
	h.heap[1] = h.heap[h.size]
	h.size -= 1
	h.maxHeapify(1)

	return max
}

func (h *Heap) maxHeapify(idx int) {
	left := idx * 2
	right := left + 1
	largest := idx

	if left <= h.size {
		if h.isHigh(h.heap[left], h.heap[idx]) {
			largest = left
		}
		if right <= h.size && h.isHigh(h.heap[right], h.heap[largest]) {
			largest = right
		}
	}

	if largest != idx {
		h.heap[idx], h.heap[largest] = h.heap[largest], h.heap[idx]
		h.maxHeapify(largest)
	}
}

C++: #include<bits/stdc++.h>
#define ll long long
#define rep(i, n) for(int i=0;i<(n);++i)
#define per(i, n) for(int i=(n)-1;i>=0;--i)
#define repa(i, n) for(int i=1;i<(n);++i)
#define foreach(i, n) for(auto &i:(n))
#define pii pair<int, int>
#define pll pair<long long, long long>
#define all(x) (x).begin(), (x).end()
#define bit(x) (1ll << (x))
const ll MOD = (ll)1e9+7;
const int INF = (ll)1e9+7;
const ll INFLL = (ll)1e18;
using namespace std;
template<class t>
using vvector = vector<vector<t>>;
template<class t>
using vvvector = vector<vector<vector<t>>>;
template<class t>
using priority_queuer = priority_queue<t, vector<t>, greater<t>>;
template<class t, class u> bool chmax(t &a, u b){if(a<b){a=b;return true;}return false;}
template<class t, class u> bool chmin(t &a, u b){if(a>b){a=b;return true;}return false;}

ll modpow(ll x, ll b){
	ll res = 1;
	while(b){
		if(b&1)res = res * x % MOD;
		x = x * x % MOD;
		b>>=1;
	}
	return res;
}

ll modinv(ll x){
	return modpow(x, MOD-2);
}

bool was_output = false;
template<class t>
void output(t a){
	if(was_output)cout << " ";
	cout << a;
	was_output = true;
}
void outendl(){
	was_output = false;
	cout << endl;
}

class dijkstra{
public:
	int n;
	vvector<pll> edges;
	vector<ll> fast;
	dijkstra(int N):n(N){
		edges.resize(n);
	}

	void add_edge(int from, int to, ll cost){
		edges[from].emplace_back(to, cost);
	}

	void solve(int start){
		priority_queuer<pll> pq;
		fast.assign(n, INFLL);
		pq.emplace(0, 0);
		fast[start] = 0;
		pq.emplace(0, start);
		while(pq.size()){
			pll d = pq.top();
			pq.pop();
			if(d.first!=fast[d.second])continue;
			foreach(i, edges[d.second]){
				ll next_time = d.first + i.second;
				int to = i.first;
				if(fast[to] <= next_time)continue;
				fast[to] = next_time;
				pq.emplace(next_time, to);
			}
		}
	}
};


int main(){
	int n;
	cin >> n;
	dijkstra dij(n);
	rep(i, n){
		int from;
		cin >> from;
		int time;
		cin >> time;
		rep(j, time){
			int to;
			ll cost;
			cin >> to >> cost;
			dij.add_edge(from, to, cost);
		}
	}
	dij.solve(0);
	rep(i, n){
		output(i);
		output(dij.fast[i]);
		outendl();
	}
	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;
    
    //cout << "testing" << endl;
    
    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<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;
#define int(x) int x; scanf("%d",&x)
#define input(x) scanf("%d",&x)
#define rep(x,n) for(int x = 0; x < n; x++)
#define _br printf("\n")
#define INF 2000000000

vector<pair<int,int> > PathList[10000];
int d[10000];
bool complete[10000];

void dijkstra(int n,vector<pair<int,int> > PathList[]){
    rep(i,n){
        d[i] = INF;
        complete[i] = false;
    }
    d[0] = 0;
    
    int count = 0;
    
    while (count != n) {
        int mind = INF;
        int mindi = 0;
        
        //select
        rep(i,n){
            if (!complete[i] && d[i] < mind) {
                mind = d[i];
                mindi = i;
            }
        }
        
        complete[mindi] = true;
        count++;
        
        //update
        rep(i,PathList[mindi].size()){
            if (PathList[mindi][i].second + d[mindi] < d[PathList[mindi][i].first]) {
                d[PathList[mindi][i].first] = PathList[mindi][i].second + d[mindi];
            }
        }
    }
}


int main(){
    int(n);
    rep(i,n){
        int(k);int(num);
        rep(j,num){
            int(s);int(t);
            PathList[i].push_back(make_pair(s,t));
        }
    }
    
    dijkstra(n,PathList);
    
    rep(i,n){
        printf("%d %d\n",i,d[i]);
    }
    
    return 0;
}