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<cstdio>
#include<climits>
using namespace std;
  
#define N 10001
int n;
  
int g[N][N];
  
int weight[N];
bool us[N];
  
//prim
void prim(){
  
  int v;
   
  weight[0]=0;
    
  while(true){
    v=-1;
     
    for(int i=0;i<n;i++){
      if(us[i]!=true && (v==-1 ||weight[i]<weight[v]))v=i;
    }
  
    if(v==-1)break;
    us[v]=true;
   
  
    for(int i=0;i<n;i++){
      if(weight[i]>(g[v][i]+weight[v])){
  
        weight[i]=(g[v][i]+weight[v]);
        //      cout <<"fsafa"<<endl;
      }
    }
  }
   
}
  
  
int main(){
  
  int u,k1,c,v;
  
  for(int i=0;i<N;i++){
    for(int j=0;j<N;j++){
      g[i][j]=9953535;
    }
  }
  
  //load n
  cin >>n;
  
  //load data
  for(int i=0;i<n;i++){
    weight[i]=INT_MAX;
    us[i]=false;
    scanf("%d %d",&u,&k1);
    for(int j=0;j<k1;j++){
      scanf("%d %d",&v,&c);
      g[u][v]=c;
      //    cout <<g[i][j]<<" ";
    }
    //    cout <<endl;
  }
  
  
  
  
  //print
  prim();
  
  for(int i=0;i<n;i++){
    cout <<i<<" "<<weight[i]<<endl;
  }
delete g;
  return 0;
  
}

C++: #include <iostream>
// #include <vector> 
#include <algorithm>
#include <queue>
#include <cstdio> 
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1<<20);
int d[MAX],color[MAX];
int n;
vector<pair<int, int> > adj[MAX];

void dijkstra()
{
    priority_queue<pair<int, int> > PQ;
    for (int i = 0; i < n; i++)
    {
        d[i] = INFTY;
        color[i] = 0;
    } 
    d[0] = 0;
    PQ.push(make_pair(0,0));
    color[0] = 1;
    while (!PQ.empty())
    { 
        pair<int, int> f = PQ.top(); PQ.pop();
        int u = f.second;
        // cout<<u<<" "<<color[u]<<endl;
        color[u] = 2;
        
        //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] == 2) continue;
            if (color[v] != 2 && 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] = 1;
            } 
        } 
    } 

    return;
}


int main()
{
    //freopen("in3.txt","r",stdin);
    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(make_pair(v,c));
        } 
    } 
    dijkstra();
    for (int i = 0; i < n; i++)
    {
        cout<<i<<" "<<d[i]<<endl; 
    } 
    return 0;
}

C++: #include <climits>
#include <iostream>
#include <queue>
#include <utility>
#include <vector>

using namespace std;

void dijkstra(vector<vector<pair<int, int>>>& g, vector<int>& weights) {
    int n_vertex = weights.size();
    vector<bool> visited(n_vertex, false);

    auto pq_compare = [](pair<int, int>& a, pair<int, int>& b) {
        return a.second > b.second;
    };
    priority_queue<pair<int, int>, vector<pair<int, int>>, decltype(pq_compare)>
        pq(pq_compare);

    weights[0] = 0;
    pq.push(make_pair(0, weights[0]));
    while (!pq.empty()) {
        pair<int, int> min_pair = pq.top();
        pq.pop();
        int min_idx = min_pair.first;

        if (min_pair.second > weights[min_idx])
            continue;

        visited[min_idx] = true;

        for (int i = 0; i < g[min_idx].size(); ++i) {
            int adj = g[min_idx][i].first;
            int weight_via_idx = weights[min_idx] + g[min_idx][i].second;
            if (!visited[adj] && weight_via_idx < weights[adj]) {
                weights[adj] = weight_via_idx;
                pq.push(make_pair(adj, weights[adj]));
            }
        }
    }
}

int main() {
    int n;
    cin >> n;

    vector<vector<pair<int, int>>> 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[i].push_back(make_pair(v, c));
        }
    }

    vector<int> weights(n, INT_MAX);
    dijkstra(g, weights);
    for (int i = 0; i < n; ++i)
        cout << i << ' ' << weights[i] << '\n';
}