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;

#define Vi vector<int>
#define FOR(i,s,e) for (int i=s; i<e; i++)
#define ITER(v) v.begin(), v.end()

constexpr int N_MAX = 10000;
constexpr int INF   = 1<<30;

using IPAIR = pair<int, int>;

vector<IPAIR> weight[N_MAX];
int dis[N_MAX];

void set_shortest_distance(const int n) {
    FOR(i,0,n) {
        dis[i] = INF;
    }

    bool ismember[n] = { false };

    priority_queue<IPAIR, vector<IPAIR>, greater<IPAIR>> pq;
    pq.push(make_pair(0, 0));

    while (!pq.empty()) {
        IPAIR top = pq.top(); pq.pop();
        const int top_i = top.second;
        if (ismember[top_i]) { continue; }
        ismember[top_i] = true;
        const int top_d = top.first;
        dis[top_i] = top_d;
        for (const IPAIR& next : weight[top_i]) {
            const int next_i = next.second;
            if (ismember[next_i]) { continue; }
            const int next_w = next.first;
            const int d = top_d + next_w;
            pq.push(make_pair(d, next_i));
        }
    }
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    int u, k, v, c;
    FOR(i,0,n) {
        cin >> u >> k;
        FOR(j,0,k) {
            cin >> v >> c;
            weight[u].push_back(make_pair(c,v));
        }
    }

    set_shortest_distance(n);

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

    return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<string>
#include<sstream>
#include<cmath>
#include<numeric>
#include<map>
#include<stack>
#include<queue>
using namespace std;
int inf = 1000000000;

class node{
public:
  int to;
  int from;
  int cost;
};

int main(void) {

  int n; scanf("%d", &n);
  vector< vector<node> > v(n);
  for(int i=0; i<n; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    for(int j=0; j<k; j++){
      int vv, c;
      scanf("%d %d", &vv, &c);
      node t;
      t.from = u;
      t.to = vv;
      t.cost = c;
      v[u].push_back(t);
    }
  }

  vector<int> dist(n, inf);
  vector<bool> vis(n, false);

  priority_queue< pair<int, int> > pq;
  pq.push(make_pair(0, 0));
  dist[0] = 0;
  vis[0] = true;
  while( !pq.empty() ){
    pair<int, int> pos = pq.top();
    pq.pop();
    int p = pos.second;
    vis[pos.second] = true;
    for(int i=0; i<v[p].size(); i++){
      if( p != v[p][i].from ) continue;
      if( dist[v[p][i].to] < dist[v[p][i].from] + v[p][i].cost ) continue;

      dist[v[p][i].to] = min(dist[v[p][i].to], dist[v[p][i].from] + v[p][i].cost);
      pq.push(make_pair(dist[v[p][i].to], v[p][i].to));
    }

  }

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

  return 0;
}

// EOF

C++: #include <map>
#include <vector>
#include <cstdio>
using namespace std;
int main(){
	int n=0,N,i,j,k,c;
	scanf("%d",&N);
	vector<map<int,int> >dist(N);
	vector<bool>used(N);
	vector<int>cost(N);
	for(;n<N;n++){
		cost[n]=9999999;
		for(scanf("%d%d",&i,&k);k--;dist[j][i]=c)scanf("%d%d",&j,&c); //i->j cost c
	}
	for(cost[0]=0;;){ //dijkstra
		int m=9999999;
		for(i=0;i<N;i++)if(!used[i]&&m>cost[i])m=cost[i];
		if(m==9999999)break;
		for(j=0;j<n;j++)if(m==cost[j]){
			map<int,int>::iterator it=dist[j].begin();
			for(used[j]=1;it!=dist[j].end();it++)if(cost[it->first]>it->second+cost[j])cost[it->first]=it->second+cost[j];
		}
	}
	for(i=0;i<n;i++)printf("%d %d\n",i,cost[i]);
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
#define MAX 10000000000

int main(void){
  ios::sync_with_stdio(false);
  cin.tie(0);

  int n; cin >> n;

  vector< vector< P > > f(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;
      f[u].push_back(make_pair(v, c));
    }
  }

  priority_queue< P, vector<P>, greater<P> > que;
  vector<ll> d(n, MAX);
  d[0] = 0;
  que.push(make_pair(0, 0));

  while(!que.empty()){
    P q = que.top(); que.pop();
    if(q.first > d[q.second]) continue;
    
    for(int i = 0; i < f[q.second].size(); i++){
      if(d[ f[q.second][i].first ] > d[q.second] + f[q.second][i].second){
        d[ f[q.second][i].first ] = d[q.second] + f[q.second][i].second;
        que.push(make_pair(d[ f[q.second][i].first ], f[q.second][i].first));
      }
    }
  }

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

  return 0;
}