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>
using namespace std;
using ll = long long;
using ull = unsigned long long;
//#define ll long long
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
#define rep(i, n) REP(i, 0, n)
#define rep_rev(i, n) for (int (i) = (int)(n) - 1 ; (i) >= 0 ; --(i))
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
#define all(x) (x).begin(),(x).end()
ll t1,t2;
const ll mod = 1000000007;
const int INF = 1e9;
const ll INFLONG = 1e18;
void swap(ll *x,ll *y){
  ll tmp;
  tmp = *x;
  *x = *y;
  *y = tmp;
}
ll n;
vector<pair<ll,ll>> vec[10000];
vector<ll> dis(10000,INFLONG);
vector<ll> visited(10000,0);
void dij(ll k){
  priority_queue<pair<ll,ll>> pq; // -c -> v

  dis[k] = 0;
  pq.push(make_pair(0,k));
  pair<ll,ll> f;
  ll u,v;
  while(!pq.empty()){
    f = pq.top();
    pq.pop();
    u = f.second;
    if(visited[u]){
      continue;
    }
    visited[u] = 1;
    for(auto itr:vec[u]){
      v = itr.second;
      if(visited[v]){
        continue;
      }
      if(dis[v] > dis[u] + itr.first){
        dis[v] = dis[u] + itr.first;
        pq.push(make_pair(dis[v] * (-1),v));
      }
    }
  }
}
int main(){
  cin >> n;
  ll u,k,v,c;
  rep(i,n){
    cin >> u >> k;
    rep(j,k){
      cin >> v >> c;
      vec[u].emplace_back(make_pair(c,v));
    }
  }
  dij(0);
  rep(i,n){
    cout << i << " " << dis[i] << endl;
  }
}

C++: #include <iostream>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <algorithm>
#include <cmath>
#include <string>
using namespace std;
typedef long long lli;
typedef vector<lli> vll;
typedef vector<bool> vbl;
typedef vector<vector<lli> > mat;
typedef vector<vector<bool> > matb;
typedef vector<string> vst;
typedef pair<lli,lli> pll;
typedef pair<double,double> pdd;
typedef vector<map<lli,lli> > graph;

lli n;
graph g;
lli u,k,v,c;
priority_queue<pll,vector<pll>,greater<pll> > q;
vbl vis;
vll ans;

int main(){
    cin >> n;
    g = graph(n);
    for(lli i = 0;i < n;i++){
        cin >> u >> k;
        for(lli i = 0;i < k;i++){
            cin >> v >> c;
            g[u][v] = c;
        }
    }
    vis = vbl(n);
    ans = vll(n);
    q.push(pll(0,0));
    while(!q.empty()){
        lli d = q.top().first;
        lli p = q.top().second;
        q.pop();
        if(vis[p]) continue;
        vis[p] = true;
        ans[p] = d;
        for(auto itr = g[p].begin();itr != g[p].end();itr++){
            if(!vis[itr->first]) q.push(pll(d+itr->second,itr->first));
        }
    }
    for(lli i = 0;i < n;i++) cout << i << " " << ans[i] << endl;
    return 0;
}

C++: #include <cstdio>
#include <queue>
#include <algorithm>
#include <utility>
#include <vector>
#include <functional>
using namespace std;

typedef pair<int,int> pii;

int main(){
	int n;
	scanf("%d", &n);
	vector<vector<pii> > G(n);
	for(int i = 0; i < n; ++i){
		int u, k, v, c;
		scanf("%d%d", &u, &k);
		for(int j = 0; j < k; ++j){
			scanf("%d%d", &v, &c);
			G[u].push_back(pii(c, v));
		}
	}

	vector<int> d(n, 1 << 30);
	d[0] = 0;
	priority_queue<pii,vector<pii>,greater<pii> > pq;
	pq.push(pii(0, 0));
	while(!pq.empty()){
		int c = pq.top().first;
		int u = pq.top().second;
		pq.pop();
		if(d[u] != c){ continue; }
		for(int i = 0; i < G[u].size(); ++i){
			int b = c + G[u][i].first;
			int v = G[u][i].second;
			if(d[v] > b){
				d[v] = b;
				pq.push(pii(b, v));
			}
		}
	}
	
	for(int i = 0; i < n; ++i){
		printf("%d %d\n", i, d[i]);
	}
}

C++: #include<stdio.h>
#include<vector>
#include<queue>
#include<map>
#include<algorithm>
#include<queue>
#include<functional>
using namespace std;
int main(){
	int a;
	int b;
	int s;
	int t;
	vector<int> n[100000];
	int nn[100000];
	vector<int> x[100000];
	priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > >y;
	vector<pair<int, int> >::iterator yy;
	int z;
	int d[100000];
	int e;
	int c[100000];
	int zz;
	pair<int, int>pai;
	for (int i = 0; i < 100000; i++){
		d[i] = 1000000009;
		c[i] = 0;
	}
	scanf("%d", &a);
	for (int i = 0; i < a; i++){
		scanf("%d %d", &s, &b);
		for (int j = 0; j < b; j++){
			scanf("%d %d", &t, &e);
			n[s].push_back(t);
			nn[s]++;
			x[s].push_back(e);

		}
	}
	d[0] = 0;
	y.push(std::make_pair(d[0], 0));
	for (int i = 0; y.empty() == 0; i++){
		zz = 0;
		for (int j = 0; y.empty() == 0 && zz == 0; j++){
			pai = y.top();
			z = pai.second;
			if (c[z] == 0)zz++;
			else y.pop();
		}
		if (zz == 0)break;
		c[z] = 1;
		for (int j = 0; j < nn[z]; j++){
			if (d[z] + x[z][j] < d[n[z][j]])
			{
				d[n[z][j]] = d[z] + x[z][j];
				y.push(std::make_pair(d[n[z][j]], n[z][j]));
			}
		}
		y.pop();
	}
	for (int i = 0; i<a; i++)printf("%d %d\n",i,d[i]);
		return 0;
}