Go: package main

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

type Item struct {
	value    int // The value of the item; arbitrary.
	priority int // The priority of the item in the queue.
	// The index is needed by update and is maintained by the heap.Interface methods.
	index int // The index of the item in the heap.
}
type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }
func (pq PriorityQueue) Less(i, j int) bool {
	return pq[i].priority < pq[j].priority
}
func (pq PriorityQueue) Swap(i, j int) {
	pq[i], pq[j] = pq[j], pq[i]
	pq[i].index = i
	pq[j].index = j
}
func (pq *PriorityQueue) Push(x interface{}) {
	n := len(*pq)
	item := x.(*Item)
	item.index = n
	*pq = append(*pq, item)
}
func (pq *PriorityQueue) Pop() interface{} {
	old := *pq
	n := len(old)
	item := old[n-1]
	item.index = -1 // for safety
	*pq = old[0 : n-1]
	return item
}

type Q struct {
	pq *PriorityQueue
	ds map[int]int // It has always same value as pq. For random access.
}

func newQ() *Q {
	pq := new(PriorityQueue)
	heap.Init(pq)
	return &Q{
		pq: pq,
		ds: make(map[int]int),
	}
}
func (q *Q) pop() (u, d int) {
	item := heap.Pop(q.pq).(*Item)
	delete(q.ds, item.value)
	return item.value, item.priority
}
func (q *Q) get(u int) (int, bool) { // returns d
	d, ok := q.ds[u]
	return d, ok
}
func (q *Q) set(u, d int) {
	q.ds[u] = d
	for _, item := range *q.pq {
		if item.value != u {
			continue
		}

		item.priority = d
		heap.Fix(q.pq, item.index)
		return
	}
	heap.Push(q.pq, &Item{
		priority: d,
		value:    u,
	})
}
func (q *Q) len() int {
	return len(q.ds)
}

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := newQ()
	q.set(0, 0)
	visited := make(map[int]struct{})
	out := make([]int, n)

	for q.len() > 0 {
		u, d := q.pop()
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			dd := d + c
			if d, ok := q.get(uu); !ok || d > dd {
				q.set(uu, dd)
			}
		}

		out[u] = d
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

C++: #include <iostream> 
#include <queue>
#include <algorithm>
#define MAX 1000
#define INF (1<<21)
#define WHITE 0
#define GRAY  1
#define BLACK 2
using namespace std;

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

void Dijkstra() 
{
    priority_queue<pair<int,int>> PQ;
    int next, min_cost;
    int color[n], dist[n];

    for (int i = 0; i < n; ++i) 
    {
        color[i] = WHITE;
        dist[i] = INF;
    }

    dist[0] = 0;
    PQ.push(make_pair(0, 0));
    color[0] = GRAY;

    while(! PQ.empty())
    {
        pair<int, int> next = PQ.top(); PQ.pop();
        int u = next.second;

        color[u] = BLACK;

        if (dist[u] < next.first * (-1)) continue;

        for (int i = 0; i < adj_list[u].size(); ++i) 
        {
            int v = adj_list[u][i].first;
            if (color[v] == BLACK) continue;
            if (dist[v] > dist[u] + adj_list[u][i].second)
            {
                color[v] = GRAY;
                dist[v] = dist[u] + adj_list[u][i].second;
                PQ.push(make_pair(dist[v]*(-1), v));
            }
        }
    }
    
    int sum = 0;
    for (int i = 0; i < n; ++i) 
    {
        cout << i << ' ' << (dist[i] != INF ? dist[i] : -1) << endl; 
    }
}

int main() 
{
    int id, deg, v, w;

    cin >> n;
    for (int i = 0; i < n; ++i) 
    {
        cin >> id >> deg;
        for (int j = 0; j < deg; ++j) 
        {
            cin >> v >> w;
            adj_list[id].push_back(make_pair(v, w));
        }
    }

    Dijkstra();

    return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<queue>
#include<vector>
#include<utility>
#include<limits>
using namespace std;
typedef pair<int, int> Edge;
const int MAX = 1000000000;
int main()
{
	int n; cin >> n;
	vector< vector< Edge > > lists;

	for (int i = 0; i < n; i++)
	{
		vector<Edge> list;
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++)
		{
			Edge edge;
			cin >> edge.second >> edge.first;
			list.push_back(edge);
		}
		lists.push_back(list);
	}

	vector<int> costs(n, MAX);
	costs[0] = 0;
	priority_queue<Edge> queue;
	for (Edge edge : lists[0])
		queue.push(edge);

	while (!queue.empty())
	{
		Edge edge = queue.top(); queue.pop();
		int dest = edge.second;
		int cost = edge.first;
		if (costs[dest] < cost)continue;
		int new_cost = costs[edge.second] = edge.first;

		for (Edge next : lists[dest])
		{
			next.first += new_cost;
			queue.push(next);
		}
	}
	for (int i = 0; i < n; i++)
		cout << i << " " << costs[i] << endl;

	char c;
	cin >> c;

	return 0;
}

C++: #include<iostream>
#include<queue>

#include<vector>
#include<utility>

using namespace std;

#define MAX 10000
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define INFTY 1<<21

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

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

  d[0] = 0;
  color[0] = GRAY;
  PQ.push(make_pair(d[0],0));

  while( !PQ.empty() ){
    pair<int, int> present = PQ.top();
    PQ.pop();

    int u = present.second;
    color[u] = BLACK;

    for(int j=0;j<adj[u].size();j++){
      int v = adj[u][j].first;
      if(color[v] != BLACK && d[v] > d[u] + adj[u][j].second ){
        d[v] = d[u] + adj[u][j].second;
        color[v] = GRAY;
        PQ.push(make_pair(-1*d[v], v));
      }   
    }
  }

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

}

int main(void){
  cin >> n;
  int u,k;
  int s,t;
  for(int i=0;i<n;i++){
    cin >> u >> k;
    for(int j=0;j<k;j++){
      cin >> s >> t;
      adj[u].push_back(make_pair(s, t));
    }
  }

  dijkstra();

  return 0;
}

C++: #include <vector>
#include <iostream>
#include <algorithm>
#include <limits>

using namespace std;
using graph = vector<vector<int>>;


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

    graph G(n, vector<int>(n, -1));
    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[u][v] = c;
        }
    }

    // Dijkstra's algorithm
    vector<int> d(n, -1);
    vector<bool> visited(n, false);

    d[0] = 0;
    visited[0] = true;
    while (1) {
        int u = -1;
        int v = -1;
        int minw = numeric_limits<int>::max();
        for (int i = 0; i < n; ++i) {
            if (!visited[i])
                continue;
            for (int j = 0; j < n; ++j) {
                if (visited[j] || G[i][j] < 0)
                    continue;
                int w = G[i][j] + d[i];
                if (w < minw) {
                    u = i;
                    v = j;
                    minw = w;
                }
            }
        }
        if (v < 0) {
            break;
        }
        d[v] = minw;
        visited[v] = true;
    }

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

    return 0;
}

C++: #include<iostream>
int main(){
  int u,k,C,V,A[1000][1000],D[1000][1000],n;
  std::cin >> n;
  for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = 200001;
  for(int i=0;i<n;i++){ 
    std::cin >> u >> k;
    for(int j=0;j<k;j++){
      std::cin >> V >> C;
      D[u][V] = C;
    } 
  }
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j]= std::min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++)std::cout << i << " " << D[0][i] << std::endl;
  return 0;
}