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>

#define INF 1000000000
using namespace std;

struct edge {
    int from;
    int to;
    int w;
};
struct node {
    node() : id {-1}, d {INF}, ns {} {};
    node(int i, vector<edge>& vec) : id {i}, d {INF}, ns {vec} {};
    int id;
    int d;
    vector<edge> ns;
};

struct node_s {
    int id;
    int d;
};

vector<int> dijkstra(node* graph, int n, int st){
    auto ds = vector<int>(n, INF);
    auto comp = [](node_s* x, node_s* y){return x->d > y->d;};
    priority_queue<node_s*, vector<node_s*>, decltype(comp)> que(comp);
    node_s* start = new node_s {graph[st].id, 0};
    que.push(start);
    while(que.size()){
        node_s* n = que.top();
    //    cout << n->id << ' ' << n->d << endl;
        que.pop();
        if(n->d < ds[n->id]){
            ds[n->id] = n->d;
            for(auto e : graph[n->id].ns){
                if(ds[e.to] < INF){
                    continue;
                }
                node_s* next_n = new node_s {graph[e.to].id, ds[n->id] + e.w};
                que.push(next_n);
            }
        }
        delete n;
    }
    return ds;
}

int main(){
    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);
    int n;
    cin >> n;
    node graph[n];
    for(int i = 0; i < n; ++i){
        int id;
        int m;
        cin >> id >> m;
        auto vec = vector<edge>(m);
        int v, c;
        for(int j = 0; j < m; ++j){
            cin >> v >> c;
            vec[j] = edge {id, v, c};
        }
        graph[id] = node(id, vec);
    }
    auto ds = dijkstra(graph, n, 0);
    for(int i = 0; i < n; ++i){
        cout << i << ' ' << ds[i] << endl;
    }
}

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

struct Edge{
    ll target;
    ll weight;
};

struct State{
    ll node;
    ll sum_of_weight;

    bool operator < (const State& s)  const {
        return sum_of_weight > s.sum_of_weight;
    }
};

typedef vector<vector<Edge> > graph;

void dijkstra(graph &g, vector<ll>&d, ll start){

    priority_queue<State> pq;
    pq.push(State{start,0});

    while( pq.size() ){

        State s = pq.top(); pq.pop();

        if( d[s.node] != -1 ) continue;
        d[s.node] = s.sum_of_weight;

        for(auto edge: g[s.node]) {
            if( d[edge.target] != -1 ) continue;
            pq.push(State{edge.target, s.sum_of_weight + edge.weight});

        }
    }

}


int main(){

    ll N;
    cin >> N;

    graph G(N);
    for (int i = 0; i < N; i++)
    {
        ll u,k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            ll v,c;
            cin >> v >> c;
            G[u].push_back(Edge{v,c});
        }
    }

    vector<ll> d(N,-1);

    ll count = 1;
    dijkstra(G,d,0);

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

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

#define MAX 10000
#define WHITE 0
#define GRAY 1
#define BLACK 2
static int INF = (1<<20);

void dijkstra(void);

int n;
int M[MAX][MAX];

int main(){
  int i,j;
  int c,k,u,v;
  cin >> n;
  for( i = 0; i < n; i++){
    for(j = 0; j < n; j++){
      //M[i][j] = INFINITY;
      M[i][j] = INF;
    }
  }
  for(i = 0; i < n; i++){
    cin >> u;
    cin >> k;
    for(j = 0; j < k; j++){
      cin >> v;
      cin >> c;
      M[u][v] = c;
    }
  }
  dijkstra();
  return 0;
}

void dijkstra(){
  int minV;
  int d[MAX],color[MAX];
  int u,v;
  int i;
  for(i = 0; i < n; i++){
    //d[i] = INFINITY;
    d[i] = INF;
    color[i] = WHITE;
  }
  d[0] = 0;
  color[0] = GRAY;
  while(1){
    //minV = INFINITY;
    minV = INF;
    u = -1;
    for(i = 0; i < n; i++){
      if(minV > d[i] && color[i] != BLACK){
        u = i;
        minV = d[i];
      }
    }
    if(u == -1){
      break;
    }
    color[u] = BLACK;
    for(v = 0; v < n; v++){
      //if(color[v] != BLACK && M[u][v] != INFINITY){
      if(color[v] != BLACK && M[u][v] != INF){
        if(d[v] > d[u] + M[u][v]){
          d[v] = d[u] + M[u][v];
          color[v] = GRAY;
        }
      }
    }
    }
    for(i = 0; i < n; i++){
      //cout << i << " " << (d[i] == INFINITY ? -1 : d[i]) << endl;
      cout << i << " " << (d[i] == INF ? -1 : d[i]) << endl;
    }
  }