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 ll = long long;
using namespace std;
#define _overload3(_1, _2, _3, name, ...) name
#define _rep(i, n) repi(i, 0, n)
#define repi(i, a, b) for(int i = int(a); i < int(b); ++i)
#define rep(...) _overload3(__VA_ARGS__, repi, _rep, )(__VA_ARGS__)
#define all(x) (x).begin(), (x).end()
const long long INFLL = 1LL << 60;
const int INFINT = 1 << 30;
const long long MOD = 1e9 + 7;

template <class T> void vecout(T V) {
    auto t = V.begin();
    while(t != V.end()) {
        cout << " " << *t++;
        // if(t != V.end()) cout << " ";
    }
    cout << endl;
};

struct edge {
    int t;
    int c;
    edge(int a, int b) {
        t = a;
        c = b;
    }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n, u, k, v, c;
    cin >> n;
    vector<edge> E[n];
    rep(i, n) {
        cin >> u >> k;
        rep(j, k) {
            cin >> v >> c;
            edge tmp(v, c);
            E[u].push_back(tmp);
        }
    }

    priority_queue<pair<int, int>, vector<pair<int, int>>,
                   greater<pair<int, int>>>
        Q; // cost,V

    int d[n];
    fill(d, d + n, INFINT);
    Q.push(make_pair(0, 0));

    int fix = 0;
    while(fix < n && !Q.empty()) {
        pair<int, int> v = Q.top();
        Q.pop();
        if(d[v.second] != INFINT) continue;
        d[v.second] = v.first;
        fix++;
        for(auto e : E[v.second]) {
            if(d[e.t] == INFINT) {
                Q.push(make_pair(v.first + e.c, e.t));
            }
        }
    }

    rep(i, n) cout << i << " " << d[i] << "\n";
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
typedef pair<int, long> P;
typedef struct edge{ long cost; int to; }edge;

const long INF = 1e11;

int main(){
  int n; cin >> n;
  long d[n];
  vector<edge> G[n];
  for(int i=0; i<n; i++){
    d[i] = INF;
    int u, k; cin >> u >> k;
    int v, c;
    for(int j=0; j<k; j++){
      cin >> v >> c;
      edge e; e.to = v; e.cost = c;
      G[u].push_back(e);
    }
  }
  priority_queue<P, vector<P>, greater<P>> que;
  d[0] = 0;
  que.push(P(0, 0));
  while(!que.empty()){
    P v = que.top(); que.pop();
    if(d[v.second] < v.first) continue;
    for(int i=0; i<G[v.second].size(); i++){
      edge e = G[v.second][i];
      if(d[e.to] > d[v.second] + e.cost){
        d[e.to] = d[v.second] + e.cost;
        que.push(P(d[e.to], e.to));
      }
    }
  }
  for(int i=0; i<n; i++){
    cout << i << " " << d[i] << endl;
  }
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int, int> > adj[MAX];

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;

        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;
                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;
}

C++: #include<iostream>
#include<queue>
#include<vector>
using namespace std;

static const int MAX = 10000;
static const int INF = (1<<21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n;
vector<pair<int,int>> adj[MAX];

void dijkstra(){
    int color[MAX], d[MAX];

    for(int i = 0; i < n; i++){
        color[i] = WHITE;
        d[i] = INF;
    }

    d[0] = 0;

    // pair<vに到達するまでのスコア、v>
    priority_queue<pair<int,int>> pq;
    pq.push({0,0});
    color[0] = GRAY;

    while(!pq.empty()){
        pair<int,int> p = pq.top(); pq.pop();
        int u = p.second;
        
        color[u] = BLACK;
        if(d[u] < p.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;
                pq.push({d[v]*(-1), v});
                color[v] = GRAY;
            }
        }
    }

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

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

   dijkstra();

   return 0;
}