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 <cstring>
#include <vector>
#include <queue>
#include <functional>
using namespace std;

const int Max = 10005;
const int INF = (1<<29);
struct Node
{
    int v, c;
    bool operator < (const Node& a) const{
        return c > a.c;
    }
};

int n, color[Max], d[Max], p[Max];
int u, k, v, c;
vector<Node> G[Max];
priority_queue<Node> pq;
Node pn;

void dijstra()
{
    memset(color, -1, sizeof(color));
    for(int i=0; i<n; i++)
    {
        d[i] = INF;
    }
    d[0] = 0;
    p[0] = -1;
    pn = {0, d[0]};
    pq.push(pn);

    while(!pq.empty())
    {
        pn = pq.top(); pq.pop();
        int u = pn.v;
        color[u] = 0;
     
        for(int j=0; j<G[u].size(); j++)
        {
            int v = G[u][j].v;
            if(color[v]!=0 && d[u]+G[u][j].c<d[v])
            {
                d[v] = G[u][j].c+d[u];
                pn = {v, d[v]};
                pq.push(pn);
                p[j] = u;//j的父节点为u，有利于重建MST
            }
        }
    }
    //打印输出
    for(int i=0; i<n; i++)
    {
        if(d[i]==INF)
            cout << i << " " << -1 << endl;
        else
            cout << i << " " << d[i] << endl;
    }
}

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

    dijstra();
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

const int INFY = numeric_limits<int>().max();
typedef pair<int, int> pa;

class graph {
public:
    graph(int n): n_(n), adj_(n) {
    }
    void add(int u, int v, int weight) {
        adj_[u].push_back(pa(weight, v));
    }
    vector<int> dijkstra(int start) {
        vector<int> d(n_, INFY);
        vector<bool> visited(n_, false);
        priority_queue<pa, vector<pa>, greater<pa>> q;
        d[0] = 0;
        q.push(pa(0, start));
        while(!q.empty()) {
            int uw = q.top().first;
            int u = q.top().second;
            q.pop();
            visited[u] = true;
            if (d[u] < uw) continue;
            for (auto pav : adj_[u]) {
                int v = pav.second;
                int w = pav.first;
                if (visited[v]) continue;
                if(d[u] + w < d[v]) {
                    d[v] = d[u] + w;
                    q.push(pa(d[v], v));
                }
            }
        }
        return d;
    }
private:
    int n_;
    vector<vector<pa>> adj_;
};


int main() {
    int n;
    cin >> n;
    graph g(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;
            g.add(u, v, c);
        }
    }
    auto d = g.dijkstra(0);
    for (int i = 0; i < n; ++i) {
        cout << i << " " << (d[i] == INFY ? -1 : d[i]) << endl;
    }
}

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

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;
}