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<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
using namespace std;
 
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef stack<int> SI;
typedef queue<int> QI;
typedef pair<int,int> PII;
typedef long long LL;
 
#define d(x)  cout<<#x<<" = "<<(x)<<endl;
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define EMP empty()
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define REACH(i,c) for(typeof((c).rbegin()) i=(c).rbegin(); i!=(c).rend(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c,n) sort(c,c+n)
#define VSORT(c) sort((c).begin(),(c).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define DFOR(i,b,a) for(int i=(b)-1;i>=(a);--i)
#define DREP(i,n) DFOR(i,n,0)
#define INF 1000000000
 
const double EPS = 1e-10;
const double PI  = acos(-1.0);
////////////////////////////////////////////////
static const int MAX=10000;
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;
 
int n;
vector<PII> adj[MAX];
void dijkstra()
{
    priority_queue<PII> PQ;
    int color[MAX];
    int d[MAX];
    REP(i,n)
    {
        d[i]=INF;
        color[i]=WHITE;
    }
     
    d[0]=0;
    PQ.push(MP(0,0));
    color[0]=GRAY;
     
    while(!PQ.EMP)
    {
        PII f=PQ.top();
        PQ.pop();
        int u=f.second;
        color[u]=BLACK;
         
        if(d[u]<f.first*(-1))continue;
         
        REP(j,SZ(adj[u]))
        {
            int v=adj[u][j].first;
            if(color[v]==BLACK)continue;
            if(d[v]>d[u]+adj[u][j].second)
            {
                d[v]=d[u]+adj[u][j].second;
                PQ.push(MP(d[v]*(-1),v));
                color[v]=GRAY;
            }
        }
    }
    REP(i,n)
    {
        cout<<i<<" "<<(d[i]==INF?-1:d[i])<<endl;
    }
}
 
int main()
{
    int k,u,c,v;
    cin>>n;
    REP(i,n)
    {
        cin>>u>>k;
        REP(j,k)
        {
            cin>>v>>c;
            adj[u].PB(MP(v,c));
        }
    }
     
    dijkstra();
     
    return 0;
}

C++: //Single Source Shortest Path II
#include <iostream>
#include <vector>
#include <queue>
#include <climits>

using namespace std;

static const int N = 10000;
static const int WHITE = 0;
static const int BLACK = 1;
int d[N];

void dijkstra(vector<vector<pair<int, int>>> G, int n) {
    int colors[n];
    for(int i = 0; i < n; i++) {
        colors[i] = WHITE;
        d[i] = INT_MAX;
    }

    priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > pq;

    d[0] = 0;
    pq.push(make_pair(0, 0));
    while(!pq.empty()) {
        pair<int, int> f = pq.top();
        pq.pop();
        
        int u = f.second;
        if(d[u] < f.first) continue;
        if(colors[u] == BLACK) continue;
        for(int i = 0; i < G[u].size(); i++) {
            if(d[G[u][i].first] > f.first + G[u][i].second) {
                d[G[u][i].first] = f.first + G[u][i].second;
                pq.push(make_pair(d[G[u][i].first], G[u][i].first));
            }

        }
    }
}

int main() {
    int n, u, k, v, c;
    cin >> n;
    vector<vector<pair<int, int>>> G(n);

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

    dijkstra(G, n);

    for(int i = 0; i < n; i++) cout << i << " " << d[i] << endl;

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
using ll = long long;
using P = pair<int, int>;
static const int MAX = 10000;
static const int INFTY = (1<<20);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int>> adj[MAX]; // 重みつき有向グラフの隣接リスト表現

void dijkstra() {
    priority_queue<pair<int, int>> PQ;
    int color[MAX];
    int d[MAX];
    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
        color[i] = WHITE;
    }

    d[0] = 0;
    PQ.push(make_pair(0, 0));
    color[0] = GRAY;

    while(!PQ.empty()) {
        pair<int, int> f = PQ.top(); PQ.pop();
        int u = f.second;

        color[u] = BLACK;

        // 最小値を取り出し、それが最短でなければ無視
        if (d[u] < f.first * (-1)) continue;

        for (int j = 0; j < adj[u].size(); j++) {
            int v = adj[u][j].first;
            if (color[v] == BLACK) continue;
            if (d[v] > d[u] + adj[u][j].second) {
                d[v] = d[u] + adj[u][j].second;
                // priority_queue はデフォルトで大きい値を優先するため -1 を掛ける
                PQ.push(make_pair(d[v] * (-1), v));
                color[v] = GRAY;

            }
        }
    }

    for (int i = 0; i < n; i++) {
        cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
    }
}

int main() {
    int k, u, v, c;

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

    dijkstra();

    return 0;
}