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<algorithm>
#include<queue>
#include<vector>
#include<utility>
#include<limits>
using namespace std;
typedef pair<int, int> Edge;
int main()
{
	int n; cin >> n;
	vector< vector< Edge > > lists;

	for (int i = 0; i < n; i++)
	{
		vector<Edge> list;
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++)
		{
			Edge edge;
			cin >> edge.second >> edge.first;
			list.push_back(edge);
		}
		lists.push_back(list);
	}

	vector<int> costs(n, INT32_MAX);
	costs[0] = 0;
	priority_queue<Edge> queue;
	for (Edge edge : lists[0])
		queue.push(edge);

	while (!queue.empty())
	{
		Edge edge = queue.top(); queue.pop();
		int dest = edge.second;
		int cost = edge.first;
		if (costs[dest] < cost)continue;
		int new_cost = costs[edge.second] = edge.first;

		for (Edge next : lists[dest])
		{
			next.first += new_cost;
			if(costs[next.second]== INT32_MAX)
				queue.push(next);
		}
	}
	for (int i = 0; i < n; i++)
		cout << i << " " << costs[i] << endl;

	char c;
	cin >> c;

	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
#define INF 1<<21
#include<vector>
static const int N = 10000;
using namespace std;
vector<pair<int,int> > A[N];
int n;
void dajkstra(void){
    priority_queue<pair<int, int> > PQ;
    int d[N],color[N];
    for(int i=0;i<n;i++){
        d[i] = INF;
        color[i] = 0;
    }
    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] = 1;
        if(d[u]<f.first*(-1)){
                continue;
        }
        for(int j=0;j<A[u].size();j++){
            int v = A[u][j].first;
            if(color[v]==1){
                continue;
            }
            if(d[u] + A[u][v].second < d[v]){
                d[v] = d[u] + A[u][v].second;
                PQ.push(make_pair(d[v]*(-1),v));
            }
        }
    }
    for(int i=0;i<n;i++){
        cout << i << ' ' << d[i] << endl;
    }
}
int main(void){
    int u,v,adj,key;
    cin >> n;
    for(int i=0;i<n;i++){
        cin >> u >> adj;
        for(int j=0;j<adj;j++){
            cin >> v >> key;
            A[u].push_back(make_pair(v,key));
        }
    }
    dajkstra();
    return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <vector>
#include <string>
#include <queue>
using namespace std;
const int INF = 1 << 30;
const int NIL = -1;
const int MAXN = 10005;
int vis[MAXN];
int d[MAXN];
int head[500005];
int n;
int cnt;
struct Edge {
	int to, next, w;
	Edge() {}
} edge[500005];

void add(int u, int v, int w)
{
	edge[cnt].to = v;
	edge[cnt].w = w;
	edge[cnt].next = head[u];
	head[u] = cnt++;
}

struct Node {
	int u, w;
	Node (int _u, int _w) :u(_u), w(_w) {}
	friend bool operator<(const Node& a, const Node& b)
	{
		return a.w > b.w;
	}
};

void dijkstra(int s)
{
	priority_queue<Node> q;
	for (int i = 0; i < n; ++i)
		d[i] = INF, vis[i] = false;
	d[s] = 0;
	
	Node t(s, 0);
	q.push(t);
	int u, v, w;
	int count = 0;
	while (!q.empty() && count < n - 1)
	{
		t = q.top();
		q.pop();
		u = t.u;
		if (d[u] < t.w)
			continue;
		vis[u] = true;
		++count;
		for (int i = head[u]; i != NIL; i = edge[i].next)
		{
			v = edge[i].to;
			w = edge[i].w;
			if (!vis[v] && d[v] > d[u] + w)
			{
				d[v] = d[u] + w;
				q.push(Node(v, d[v]));
			}
		}
	}
	if (count == n - 1)
		for (int i = 0; i < n; ++i)
			printf("%d %d\n", i, d[i]);

}

int main(void)
{
	int k, s, e, w;
	scanf("%d", &n);
	memset(head, NIL, sizeof(-1));
	cnt = 0;
	for (int i = 0; i < n; ++i)
	{
		scanf("%d%d", &s, &k);
		while (k--)
		{
			scanf("%d %d", &e, &w);
			add(s, e, w);
		}
	}
	dijkstra(0);

	return 0;
}