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 <iostream>
#include <vector>
#include <climits>
#include <queue>

using namespace std;

const int kSize = 100001;

vector<int> V;

struct Node {
    int to;
    int weight;

    Node(int _to, int _weight) {
        to = _to;
        weight = _weight;
    }
};

int n;
vector<Node> adj[kSize];
bool isMarked[kSize];
int tree[kSize];
int dis[kSize];

void Dijkstra(int s) {
    dis[s] = 0;
    priority_queue<pair<int, int>, vector<pair<int, int> >, greater<> > pq;

    pq.push(make_pair(s, 0));
    //isMarked[s] = true;
    tree[s] = s;

    while (!pq.empty()) {
        pair<int, int> p = pq.top();
        pq.pop();
        int from = p.first;
        for (int i = 0; i < adj[from].size(); ++i) {
            int to = adj[from][i].to;
            if (dis[from] + adj[from][i].weight < dis[to]) {
                dis[to] = dis[from] + adj[from][i].weight;
                tree[to] = from;
                pq.push(make_pair(to, dis[to]));
            }
        }
    }

}

int main() {
    fill(isMarked, isMarked + kSize, false);
    fill(dis, dis + kSize, INT_MAX);
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; ++j) {
            int v, c;
            cin >> v >> c;
            adj[u].emplace_back(v, c);
        }
    }

    Dijkstra(0);
    for (int i = 0; i < n; ++i) {
        cout << i << " " << dis[i] << endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
static const int INF=1000000;

int n;
vector<pair<int,int> > nex[10000];

void dijkstra(){ 
  priority_queue<pair<int,int> >PQ;
  int d[10000];
  int color[10000];  
  for(int i=0;i<n;i++){
    d[i]=INF;
    color[i]=0;
  }
  
  color[0]=1;
  d[0]=0;
  PQ.push(make_pair(0, 0));
  
  while( !PQ.empty() ){
    pair<int,int> f = PQ.top();PQ.pop();
    int u =f.second;
    color[u]=2;
    if(d[u] < f.first *(-1)) continue;
    
    for(int j=0;j<nex[u].size();j++){
      int v=nex[u][j].first;
      if(color[v] == 2) continue;
      if(d[v]>d[u]+nex[u][j].second){
        d[v]=d[u]+nex[u][j].second;
        PQ.push(make_pair(d[v]*(-1),v));
        color[v]=1;
      }
    }
  }
  for(int i=0;i<n;i++){
    cout<<i<<" "<<(d[i] == INF ?:d[i])<<endl;
  }
}


int main(){
  cin>>n;
  int u,k,v,c;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
      nex[u].push_back(make_pair(v,c));
    }
  }
  
  dijkstra();
  return 0;
}

C++: #include <vector>
#include <queue>
#include <stdio.h>
#include <iostream>
#include <limits>

using namespace std;

const int MAXN = 10000;
const int INF = numeric_limits<int>::max();

vector< pair<int, int> > G[MAXN];
int dist[MAXN];
int n;

void dijkstra(int start) {
  for (int i = 0; i < n; ++i) dist[i] = INF;

  priority_queue< pair<int, int>, vector< pair<int, int> >, greater< pair<int, int> > > q;
  q.emplace(0, start);
  dist[start] = 0;
  while (!q.empty()) {
    pair<int, int> cur = q.top(); q.pop();
    int v = cur.second;
    int cost = cur.first;
    if (dist[v] < cost) continue;

    for (size_t i = 0; i < G[v].size(); ++i) {
      int u = G[v][i].first;
      int new_cost = G[v][i].second + cost;
      if (dist[u] > new_cost) {
	q.emplace(new_cost, u);
	dist[u] = new_cost;
      }
    }
  }
}
int main () {
  cin >> n;

  for (int i = 0; i < n; ++i) {
    int u, k;
    cin >> u >> k;
    for (int j = 0; j < k; ++j) {
      int v, c;
      cin >> v >> c;
      G[u].emplace_back(v, c);
    }
  }
  dijkstra(0);
  for (int i = 0; i < n; ++i) {
    cout << i << " " << dist[i] << endl;
  }
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
struct edge{
  int to,cost;
};
typedef pair<int,int> P;
int V;
vector<edge> G[100000];
int d[100000];
void dijkstra(int s){
  priority_queue<P ,vector<P>,greater<P> >que;
  fill(d,d+V,1e9+1);
  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]>d[v]+e.cost){
        d[e.to]=d[v]+e.cost;
        que.push(P(d[e.to],e.to));
      }
    }
  }
}
int main(){
  int k,u,v,c;
  cin >> V;
  for(int i=0;i<V;i++){
    cin >> u >> k;
    for(int j=0;j<k;j++){
      cin >> v >> c;
      edge ed;
      ed.to=v;
      ed.cost=c;
      G[u].push_back(ed);
    }
  }
  dijkstra(0);
  for(int i=0;i<V;i++){
    cout << i << " " << d[i] << endl;
  }
  return 0;
}