Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
const INF = 1 << 60

type Edge struct {
	to, cost int
}

type Node struct {
	id, cost int
}

type PQ []Node

func (pq PQ) Len() int           { return len(pq) }
func (pq PQ) Less(i, j int) bool { return pq[i].cost < pq[j].cost }
func (pq PQ) Swap(i, j int)      { pq[i], pq[j] = pq[j], pq[i] }

func (pq *PQ) Push(x interface{}) {
	*pq = append(*pq, x.(Node))
}

func (pq *PQ) Pop() interface{} {
	old := *pq
	n := len(old)
	x := old[n-1]
	*pq = old[0 : n-1]
	return x
}

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		E[id] = make([]Edge, k)
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id][j] = Edge{to, cost}
		}
	}

	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	done := make([]bool, N)
	pq := &PQ{}
	heap.Init(pq)
	d[0] = 0
	heap.Push(pq, Node{0, 0})
	for pq.Len() > 0 {
		cur := heap.Pop(pq).(Node).id
		if done[cur] {
			continue
		}
		done[cur] = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+d[cur]
			if !done[to] && cost < d[to] {
				d[to] = cost
				heap.Push(pq, Node{to, cost})
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, d[i])
	}
	wtr.Flush()
}

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


#define MAX 10000


using namespace std;
typedef pair<int, int> pi;

vector< pi > hdrs[MAX];
priority_queue< pi, vector<pi>, greater<pi> > distances;
bool is_tree[MAX];
int d[MAX];
int n;

void dijkstra()
{
    for (int i = 0; i < n; i++) {
        is_tree[i] = false;
        d[i] = INT_MAX;
    }

    distances.push(make_pair(0, 0));
    d[0] = 0;
    while (!distances.empty()) {
        // min_distance, vertex_id
        pi now = distances.top();
        distances.pop();

        if (d[now.second] < now.first)
            continue;
        is_tree[now.second] = true;

        for (vector<pi>::iterator it = hdrs[now.second].begin(); it != hdrs[now.second].end(); it++) {
            // *(it).second is same as it->second
            if (!is_tree[(*it).second] && now.first + (*it).first < d[(*it).second]) {
                d[(*it).second] = now.first + (*it).first;
                distances.push(make_pair(d[(*it).second], (*it).second));
            }
        }
    }
}


int main()
{
    cin >> 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;
            // cost, vertex_id
            hdrs[u].push_back(make_pair(c, v));
        }
    }

    dijkstra();

    for (int i = 0; i < n - 1; i++) {
        cout << i << " " << d[i] << endl;
    }
    cout << n - 1<< " " << d[n - 1] << endl;

    return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <climits>
#include <queue>
#include <map>
using namespace std;

typedef map<int, int>::iterator mitr;

map<int, int> w[10000];
int d[10000];
char pos[10000];

priority_queue<pair<int,int> > others;
pair<int,int> p;

void findPath(){
    p = others.top();
    others.pop();
    while(pos[p.second]){
        p = others.top();
        others.pop();
    }
    pos[p.second]=1;

    int tmpu = p.second;
    int tmpd = -p.first;

    for(mitr i=w[tmpu].begin();i!=w[tmpu].end();i++){
        if(tmpd + i->second < d[i->first]){
            d[i->first] = tmpd + i->second;
            others.push(make_pair(-d[i->first],i->first));
        }
    }
}

int main(){
    int i,j,u,k,n,v,c;

    scanf("%d",&n);
    for(i=0;i<n;i++){
        scanf("%d %d",&u,&k);
        for(j=0;j<k;j++){
            scanf("%d %d",&v,&c);
            w[u][v] = c;
        }
    }

    memset(pos,0,sizeof(char)*100);
    for(i=0;i<n;i++)d[i]=INT_MAX;
    d[0] = 0;
    others.push(make_pair(0,0));
    for(i=0;i<n;i++)findPath();
    for(i=0;i<n;i++)printf("%d %d\n",i,d[i]);

    return 0;
}

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

int n;
const int INF = 1000000;
vector<vector<int> > v, c;
vector<int> w;

void trip(int id, int dp) {
	if (dp > n)
		return;

	for (int j = 0; j < (int)v[id].size(); j++) {
		if (w[v[id][j]] > w[id] + c[id][j]) {
			w[v[id][j]] = w[id] + c[id][j];
			trip(v[id][j], dp + 1);
		}
	}
}

int main()
{
	cin >> n;

	int u, k, v1, c1;
	v.resize(n);
	c.resize(n);
	w.assign(n, INF);

	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v1 >> c1;
			v[u].push_back(v1);
			c[u].push_back(c1);
		}
	}

	w[0] = 0;
	trip(0, 1);

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

	return 0;
}

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;
  
}