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>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>

using namespace std;
using ll = long long int;
#define rep(i,n) for(int i = 0; i < n; i++)
#define FOR(i, a, b)  for(int i = (a); i < (b) ; i++)

#define pb push_back
#define SORT(v,n) sort(v, v+n)
#define ALL(x) (x).begin(),(x).end()
#define debug(x) cerr << #x << ": " << x << '\n'
#define elif else if
#define itn ll
#define int ll
const int INF = 100100100;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
///                →,↑,←,↓,↗,↖,↙,↘
int dx[8] = { 1, 0, -1, 0, 1, -1, -1, 1 };
int dy[8] = { 0, 1, 0, -1, 1, 1, -1, -1 };
typedef vector<vector<int>> vvi;
typedef vector<vector<vector<int>>> vvvi;
int i, j, k;

static const int MAX = 10000;
static const int White = 0;
static const int Gray = 1;
static const int Black = 2;

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

void dijkstra() {
	int d[MAX], p[MAX], color[MAX];
	priority_queue<pair<int, int>> PQ;
	rep(i, n) {
		color[i] = White;
		d[i] = INF;
	}
	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;
		rep(j, adj[u].size()) {
			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;
			}
		}
	}
	rep(i, n) {
		cout << i << ' ' << (d[i] == INF ? -1 : d[i]) << '\n';
	}
}

signed main() {
	ios::sync_with_stdio(false);
	cin >> n;
	rep(i, n) {
		int u,k;
		cin >> u >> k;
		rep(j, k) {
			int v, c;
			cin >> v >> c;
			adj[u].pb(make_pair(v, c));
		}
	}
	dijkstra();
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
static const int MAX = 10000;
static const int INFTY = (1<<20);
static const int WHITE = 0;
static const int BLACK = 1;

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

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

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

  while(!PQ.empty()) {
    std::pair<int, int> f = PQ.top();
    PQ.pop();
    int u = f.second; // ..? これは重みでは?

    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(std::make_pair(d[v] * (-1), v));
      }
    }
  }

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

  std::cout << sum << std::endl;

}


int main() {
  int k, u, v, c;
  std::cin >> n;

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

  dijkstra();
}