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;

typedef pair<int, int> node;
typedef vector<node> Adj_list;
typedef vector<Adj_list> Adj_lists;

class less_cost{
public:
  bool operator()(const pair<int, int> lhs, const pair<int, int> rhs) const{
    return lhs.second < rhs.second;
  }
};

int main(){

  int n;
  scanf("%d", &n);

  Adj_lists adj_lists(n);

  // read weigts
  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_lists.at(u).push_back(node(v, c));
    }
  }

  // initialize cost
  vector<int> d(n, INT_MAX);
  d.at(0) = 0;
  priority_queue<node, vector<node>, less_cost> pq;
  pq.push(node(0, d.at(0)));

  //dijkstra's algorithm
  while(!pq.empty()){
    // extract node u in V-S that has minimum cost
    const node u = pq.top();
    pq.pop();

    // if u's cost is larger than d[u],
    // than ignore this one
    if(u.second < d.at(u.first)) continue;

    // update node in V-S and adjacent to u
    for(const node& v : adj_lists.at(u.first)){
      if(d.at(u.first) + v.second < d.at(v.first)){
        d.at(v.first) = d.at(u.first) + v.second;
        pq.push(make_pair(v.first, d.at(v.first)));
      }
    }
  }

  // output
  for(int i=0; i<n; i++){
    printf("%d %d\n", i, d[i]);
  }

  return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
static const int MAX = 10000;
int N;
vector<pair<int, int>> adj[MAX];
int color[MAX];
int d[MAX];
int INF = 1 << 30;

void pd() {
    for (int i = 0; i < N; i++) {
        cout << d[i] << " ";
    }
    cout << endl;
}

void pa() {
    for (int i = 0; i < N; i++) {
        cout << i << " ";
        for (int j = 0; j < adj[i].size(); j++) {
            cout << adj[i][j].second << " ";
        }
        cout << endl;
    }
    cout << endl;
}

void dijkstr() {
    int i,j;
    priority_queue<pair<int, int>> PQ;
    PQ.push(make_pair(0, 0));
    
    d[0] = 0;
    cout << N << endl;
    for (i = 0; i < N; i++) {
        pair<int, int> p = PQ.top(); PQ.pop();
        
        //int c = p.first;
        int id = p.second;
        
        color[id] = 1;
        for (j = 0; j < adj[id].size(); j++) {
            auto node = adj[id][j];
            int c = node.first;
            int k = node.second;
            if (color[k] != 1) {
                if (d[k] > d[id] + c) {
                    d[k] = d[id] + c;
                    PQ.push(make_pair(-c, k));
                }
            }
        }
    }
}



int main(int argc, const char * argv[]) {
    int i,j;
    cin >> N;
//    pd();

    for (i = 0; i < N; i++) {
        int u,k;
        cin >> u >> k;
        color[i] = 0;
        d[i] = INF;
        for (j = 0; j < k; j++) {
            int v, c;
            cin >> v >> c;
            adj[u].push_back(make_pair(c, v));
        }
    }
    
    //pa();
    
    dijkstr();
    
    for (i = 0; i < N; i++) {
        cout << i << " " << d[i] << endl;
    }
    
    
    return 0;
}

C++: #define _USE_MATH_DEFINES

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>

using namespace std;

#define MAX_V 200000

typedef pair<long long int, long long int> P;
long long int INF = 1e18;

struct edge{
	int to;
	long long int cost;
};

vector<edge> G[MAX_V];
long long int d[MAX_V];

// 速さはO(|E|log|V|)

void shortest_path(int s, int V){ // Vは頂点数
	
	priority_queue<P, vector<P>, greater<P> > que;
	
	for(int i = 0; i < V; i++){
		d[i] = INF;
	}
	d[s] = 0;
	
	que.push(P(0, s));
	
	while(!que.empty()){
		
		P p = que.top();
		que.pop();
		
		int v = p.second;
		
		if(d[v] < p.first){
			continue;
		}
		
		for(int i = 0; i < G[v].size(); i++){
			edge e = G[v][i];
			if(d[e.to] > e.cost + d[v]){
				d[e.to] = d[v] + e.cost;
				que.push(P(d[e.to], e.to));
			}
		} // 頂点への最小コストを更新
	}
}

int main(){
	
	int V;
	cin >> V;
	
	for(int i = 0; i < V; i++){
		int u, num;
		cin >> u >> num;
		for(int j = 0; j < num; j++){
			edge e;
			cin >> e.to >> e.cost;
			G[u].push_back(e);
		}
	}
	
	shortest_path(0, V);
	
	for(int i = 0; i < V; i++){
		cout << i << " " << d[i] << endl;
	}
	
	return 0;
}

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

template<class E>
using nega_queue=priority_queue<E,vector<E>,greater<E>>;

UL N;
ULL D[100000];
vector<pair<UL,ULL>> E[100000];

int main() {
 scanf("%u",&N);
 rep(i,N){
  UL u,k; scanf("%u%u",&u,&k);
  rep(j,k){
   UL v,c; scanf("%u%u",&v,&c);
   E[u].push_back({v,c});
  }
 }
 rep(i,N) D[i]=~0u;
 nega_queue<pair<ULL,UL>> G;
 G.push({0,0});
 int ans=0;
 while(G.size()){
  ULL d=G.top().first;
  UL p=G.top().second;
  G.pop();
  if(D[p]!=~0u) continue;
  D[p]=d;
  for(auto e:E[p]) G.push({d+e.second,e.first});
 }
 rep(i,N) printf("%u %llu\n",i,D[i]);
 return 0;
}