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 <cstdio>           // printf(), getc(), scanf()
#include <cctype>           // isdigit()
#include <vector>
#include <queue>            // priority_queue
#include <algorithm>        // fill()
#include <utility>          // pair

using namespace std;

static const int MAX_V = 10000;
static const int INF = 100000000;

typedef pair<int, int> P;
struct edge
{
	int to;
	int cost;
};

vector<edge> G[MAX_V];
int V;

void
dijkstra()
{
	priority_queue<P, vector<P>, greater<P> > que;
	int d[MAX_V];
	int u;
	unsigned int v; 

	fill(d, d + V, INF);
	d[0] = 0;
	que.push(P(0, 0));

	while (!que.empty())
	{
		P p = que.top(); que.pop();
		int u = p.second;
		if (d[u] < p.first)
			continue;

		for (v = 0; v < G[u].size(); ++v)
		{
			edge e = G[u][v];
			if (d[u] + e.cost < d[e.to])
			{
				d[e.to] = d[u] + e.cost;
				que.push(P(d[e.to], e.to));
			}
		}
	}

	for (u = 0; u < V; ++u)
		printf("%d %d\n", u, d[u]);
}

int
main(int argc, char** argv)
{
	edge e;
	int u, v;
	int i, j, k;
	int n;
	int c;

	c = getc(stdin);
	while (c == ' ')
		c = getc(stdin);
	
	n = 0;
	while (isdigit(c))
	{
		n = n * 10 + c - '0';
		c = getc(stdin);
	}

	V = n;
	for (i = 0; i < V; ++i)
	{
		while (c == ' ' || c == '\n')
			c = getc(stdin);

		n = 0;
		while (isdigit(c))
		{
			n = n * 10 + c - '0';
			c = getc(stdin);
		}

		u = n;
		while (c == ' ')
			c = getc(stdin);

		n = 0;
		while (isdigit(c))
		{
			n = n * 10 + c - '0';
			c = getc(stdin);
		}

		k = n;
		for (j = 0; j < k; ++j)
		{
			while (c == ' ')
				c = getc(stdin);

			n = 0;
			while (isdigit(c))
			{
				n = n * 10 + c - '0';
				c = getc(stdin);
			}

			v = n;
			while (c == ' ')
				c = getc(stdin);

			n = 0;
			while (isdigit(c))
			{
				n = n * 10 + c - '0';
				c = getc(stdin);
			}

			e.to = v;
			e.cost = n;
			G[u].push_back(e);
		}
	}

	dijkstra();
	return 0;
}

C++: #include <utility>
#include <string>
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

int n;					//えぬ
int a[100][100] = {0};	//辺の重さ
int f[100] = {0};		//その頂点が調査済みかどうか

int main(){
	cin >> n;
	//まず辺の重さをaに入れる
	for ( int i = 0; i < n; i++ ) {
		for ( int j = 0; j < n; j++ ) {
			a[i][j] = -1;
		}
	}
	a[0][0] = 0;
	for ( int i = 0; i < n; i++ ) {
		int u;
		cin >> u;
		int k;
		cin >> k;
		for ( int j = 0; j < k; j++ ) {
			int v;
			cin >> v;
			cin >> a[u][v];
		}
	}
	for ( int i = 0; i < n - 1; i++ ) {
		int k = -1;
		int v = 0;
		for ( int j = 1; j < n; j++ ) {
			if ( a[0][j] == -1 || f[j] == 1 ) continue;
			if ( k == -1 || a[0][j] < k ) {
				v = j;
				k = a[0][j];
			}
		}
		f[v] = 1;
		for ( int j = 1; j < n; j++ ) {
			if ( v == j ) continue;
			if ( a[v][j] == -1 || f[j] == 1 ) continue;
			if ( a[0][j] == -1 || a[0][j] > a[0][v] + a[v][j] ) {
				a[0][j] = a[0][v] + a[v][j];
			}
		}
	}
	for ( int i = 0; i < n; i++ ) {
		cout << i << " " << a[0][i] << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

using Weight=int;
struct Edge {
    int src,dest; Weight weight;
    bool operator<(const Edge &rhs)const{
        return weight<rhs.weight;
    }
};
using Edges=vector<Edge>;
using Graph=vector<Edges>;

const Weight INF=1e9;

void dijkstra(const Graph &g,int s,vector<Weight> &d)
{
    assert(0<=s && s<g.size());
    d.assign(g.size(),INF); d[s]=0;
    vector<int> used(g.size(),0);
    using P=pair<Weight,int>;
    priority_queue<P,vector<P>,greater<P>> que;
    que.push({0,s});
    while(!que.empty())
    {  
        auto val=que.top(); que.pop();
        Weight dist=val.first;
        int v=val.second;
        if(used[v]) continue;
        used[v]=true;
        for(auto e:g[v])
        {
            int to=e.dest;
            Weight w=e.weight;
            if(dist+w<d[to])
            {
                d[to]=dist+w;
                que.push({d[to],to});
            }
        }
    }
}

int main()
{
    int n;
    cin>>n;
    Graph g(n);
    for(int i=0;i<n;i++)
    {
        int k;
        cin>>k>>k;
        for(int j=0;j<k;j++)
        {
            int v;
            cin>>v;  
            Weight c;
            cin>>c;          
            g[i].push_back((Edge){i,v,c});
        }
    }
    vector<Weight> d;
    dijkstra(g,0,d);
    for(int i=0;i<n;i++)
    {
        cout<<i<<" "<<d[i]<<endl;
    }
    return 0;
}