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>
using namespace std;
#include<cstdio>
#include<vector>
#include<utility>
#include<queue>

typedef vector<pair<int, int> > adj;

struct current_cost
{
    int index, cost;
    bool operator < (const current_cost &cur) const
    {
        return cost > cur.cost;
    }
};

current_cost init(int i, int c)
{
    current_cost cur;
    cur.index = i, cur.cost = c;
    return cur;
}

int main()
{
    int i, n, m, next, cost;
    scanf("%d", &n);
    adj *adlist;
    adlist = new adj [n];

    for(int k = 0; k < n; k++){
        scanf("%d %d", &i, &m);
        for(int j = 0; j < m; j++){
            scanf("%d %d", &next, &cost);
            adlist[i].push_back(make_pair(next, cost));
        }
    }

    int *d;
    d = new int [n];
    for(i = 1; i < n; i++){ d[i] = 200000; }
	d[0] = 0;

    priority_queue<current_cost> C;
    current_cost cur = init(0, 0);
    C.push(cur);

    int size;
    bool *check;
    check = new bool [n];
    for(i = 0; i < n; i++){ check[i] = false; }
	int rest = n;

    while(!C.empty())
    {
        cur = C.top(); C.pop();
		i = cur.index;
        if(check[i]) continue;
        check[i] = true; rest--;
 
        size = adlist[i].size();
        for(int j = 0; j < size; j++){
            int k = adlist[i][j].first;
            if(d[i] + adlist[i][j].second < d[k]){
                d[k] = d[i] + adlist[i][j].second;
                C.push(init(k, d[k]));
            }
        }
		if(rest == 0) break;
    };
    for(i = 0; i < n; i++){ printf("%d %d\n", i, d[i]); }

    return 0;
}

C++: #include<iostream>
#include<vector>
#define INF 2<<28

using namespace std;

class Edge {
public:
	int v, u, d;
};

class Node {
public:
	int t = 0, d = -1, e = 0;
	vector<Edge> E;
};

int n, e = 0;
Node V[10000];

void Path() {
	int m = 0, v = 0, u;

	V[0].t = 1; V[0].d = 0;

	while (true) {
		if (v == n) break;

		int min = INF;
		for (int i = 0; i < n; i++) {
			if (V[i].t == 1 && V[i].d < min) { u = i; min = V[i].d; }
		}

		V[u].t = 2; v++;

		for (int i = 0; i < V[u].e; i++) {
			int j = V[u].E[i].u;
			if (V[j].t == 0) { V[j].t = 1; V[j].d = V[u].d + V[u].E[i].d; }
			if (V[j].t == 1 && V[j].d > V[u].d + V[u].E[i].d) V[j].d = V[u].d + V[u].E[i].d;
		}
	}
}

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++) {
			Edge e;
			cin >> v >> c;
			e.v = u; e.u = v; e.d = c;
			V[u].E.push_back(e); V[u].e++;
		}
	}

	Path();

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

C++: #include<cstdio>
#include<algorithm>
#include<queue>
#include<vector>
#include<map>
using namespace std;
typedef pair< int, int > Pi;
const int INF = 1 << 30;
struct edge: vector< Pi > {
  void add_edge(int to, int cost){
    push_back(Pi(to,cost));
  }
} info[100000];
int hoge[100000];

void bfs(const int& st, const int& V){
  fill_n( hoge, V, INF);
  queue< int > que;
  que.push(st);
  hoge[st] = 0;
  while(!que.empty()){
    int p = que.front();
    que.pop();
    for(int i = 0 ; i < info[p].size() ; i++){
      int cost = info[p][i].second;
      int to = info[p][i].first;
      if( cost + hoge[p] < hoge[to]){
        que.push(to);
        hoge[to] = cost + hoge[p];
      }
    }
  }
}

int main(){
  int N;
  scanf("%d", &N);
  for(int i = 0; i < N; i++){
    int u, k;
    scanf("%d %d", &u, &k);
    while(k--){
      int v, c;
      scanf("%d %d", &v, &c);
      info[u].add_edge( v, c);
    }
  }
  bfs(0, N);
  for(int i = 0 ; i < N ; i++ ){
    printf("%d %d\n", i, hoge[i]);
  }
}

C++: #include<iostream>
#include<queue>
#include<algorithm>

using namespace std;

static const int MAX = 10000;
static const int UNVISITED = 0;
static const int VISITING = 1;
static const int VISITED = 2;

static const int INFTY = (1 << 30 );


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

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

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

    while( !PQ.empty() ) {
       	pair<int, int > f = PQ.top(); PQ.pop();
       	int u = f.second;
       	s[u] = VISITED;
        
        if ( d[u] < f.first * (-1) ) continue;

        for( int j = 0; j < adj[u].size(); j++ ) {
        	int v = adj[u][j].first;
        	if( s[v] != VISITED ) {
        		if( d[v] > d[u] + adj[u][j].second ){
        			d[v] = d[u] + adj[u][j].second;
        			PQ.push(make_pair((-1) * d[v], v ));
        		}
        		
        	}
        }

    }

   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;
   	while( k-- ) {
   		cin >> v >> c;
   		adj[u].push_back( make_pair(v, c));
   	}
   }

    Dijkstra() ;

   return 0;
}