Go: package main

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

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

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

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	route := make([][]Node, n)
	weight := make([]int, n)
	for i := 0; i < n; i++ {
		weight[i] = NIL
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		route[i] = make([]Node, k)
		for j := 0; j < k; j++ {
			route[u][j] = Node{id: scanInt(), weight: scanInt()}
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for _, nextNode := range route[node.id] {
			if weight[nextNode.id] != NIL {
				continue
			}
			nextNode.weight += node.weight
			heap.Push(h, nextNode)
		}
	}

	for i, w := range weight {
		fmt.Println(i, w)
	}
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <queue>
#define MAX 10000
#define INF (1<<30)

using namespace std;
enum state{
  BLACK,
  WHITE
};

int main(){
  vector<pair<int,int>> a[MAX];
  int n; cin>>n;
  int d[MAX];
  state s[MAX];

  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;
      a[u].push_back(make_pair(v,c));
    }
  }

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

  priority_queue<pair<int,int>> q;
  q.push(make_pair(0,0));

  while(!q.empty()){
    pair<int,int> p;
    p = q.top(); q.pop();
    if(s[p.second]==BLACK) continue;
    d[p.second]=p.first*-1;
    s[p.second]=BLACK;
    
    for(auto it = a[p.second].begin(); it!=a[p.second].end(); it++){
      int i = it->first;
      int cost = it->second;
      if(s[i]==WHITE && d[i] > d[p.second] + cost ){
        d[i]=d[p.second]+cost;
        q.push(make_pair(d[i]*-1,i));
      }
    }
  }
  
  for(int i=0;i<n;i++){
    printf("%d %d\n",i,d[i]);
  }


}

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

#define MAX_NODE 10000
#define INF 1000000000

using namespace std;

struct Edge {int to, w;};
typedef pair<int, int> PII;

vector<Edge> adj[MAX_NODE];
int d[MAX_NODE];

void dijkstra(int n, int start) {
	priority_queue<PII, vector<PII>, greater<PII>> que;
	fill(d, d + n, INF);

	d[start] = 0;
	que.emplace(0, start);
	while (!que.empty()) {
		PII p = que.top();
		que.pop();
		int from = p.second;

		if (d[from] < p.first)
			continue;

		for (auto& e : adj[from])
			if (d[from] + e.w < d[e.to]) {
				d[e.to] = d[from] + e.w;
				que.emplace(d[e.to], e.to);
			}
	}
}

int main() {
	ios::sync_with_stdio(false);
	std::cin.tie(NULL);

	int n;

	cin >> n;

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		while (k--) {
			int v, c;
			cin >> v >> c;
			adj[u].push_back({v, c});
		}
	}

	dijkstra(n, 0);

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

	return 0;
}

C++: /**
 * @copyright (c) 2020 Daisuke Hashimoto
 */

#include <cstdint>
#include <iostream>
#include <queue>
#include <string>
#include <vector>

constexpr int32_t kMaxNumberOfVertices = 10000;
constexpr int32_t kInvalidIndex = -1;

// ****************************************************

void CallDijkstraAlgorithm(std::istream &input_stream);

// ****************************************************

struct Edge {
  int32_t connected_to{kInvalidIndex};
  int32_t weight{INT32_MAX};
};
struct Vertex {
  int32_t distance{INT32_MAX};
  bool distance_is_fixed{false};
  std::vector<Edge> edges_from_this_vertex;
};

class DijkstraAlgorithm {
 public:
  DijkstraAlgorithm() noexcept;
  ~DijkstraAlgorithm() noexcept;
  void SetNumberOfVertices(const int32_t number_of_vertices) noexcept;
  void AddWeight(const int32_t vertex_from, const int32_t vertex_to, const int32_t weight) noexcept;
  void CalculateShortestPaths(const int32_t start_vertex_index) noexcept;
  void Print() noexcept;

 private:
  int32_t number_of_vertices_;
  Vertex vertices_[kMaxNumberOfVertices];
  using Pair = std::pair<int32_t, int32_t>;
  std::priority_queue<Pair, std::vector<Pair>, std::greater<Pair>> priority_queue_;
};

void CallDijkstraAlgorithm(std::istream &input_stream) {
  input_stream.tie(0);
  std::ios::sync_with_stdio(false);
  DijkstraAlgorithm *single_source_shortest_path = new DijkstraAlgorithm();
  try {
    int32_t number_of_vertices;
    input_stream >> number_of_vertices;
    single_source_shortest_path->SetNumberOfVertices(number_of_vertices);
    for (int32_t i = 0; i < number_of_vertices; ++i) {
      int32_t vertex_from, number_of_edges_from_this;
      input_stream >> vertex_from >> number_of_edges_from_this;
      for (int32_t i = 0; i < number_of_edges_from_this; ++i) {
        int32_t vertex_to, weight;
        input_stream >> vertex_to >> weight;
        single_source_shortest_path->AddWeight(vertex_from, vertex_to, weight);
      }
    }
    constexpr int32_t kVertexStart = 0;
    single_source_shortest_path->CalculateShortestPaths(kVertexStart);
    single_source_shortest_path->Print();
  } catch (...) {
    std::cerr << "ERROR: CallDijkstraAlgorithm()" << std::endl;
    throw;
  }
  delete single_source_shortest_path;
}

// ****************************************************

DijkstraAlgorithm::DijkstraAlgorithm() noexcept : number_of_vertices_(0) {}

DijkstraAlgorithm::~DijkstraAlgorithm() noexcept {}

void DijkstraAlgorithm::SetNumberOfVertices(const int32_t number_of_vertices) noexcept {
  number_of_vertices_ = number_of_vertices;
}

void DijkstraAlgorithm::AddWeight(const int32_t vertex_from, const int32_t vertex_to, const int32_t weight) noexcept {
  Edge cedge;
  cedge.connected_to = vertex_to;
  cedge.weight = weight;
  vertices_[vertex_from].edges_from_this_vertex.push_back(cedge);
}

void DijkstraAlgorithm::CalculateShortestPaths(const int32_t start_vertex_index) noexcept {
  vertices_[start_vertex_index].distance = 0;
  priority_queue_.push(Pair(vertices_[start_vertex_index].distance, start_vertex_index));
  while (priority_queue_.size() > 0) {
    const int32_t shortest_index = priority_queue_.top().second;
    const int32_t shortest_distance = priority_queue_.top().first;
    vertices_[shortest_index].distance_is_fixed = true;
    priority_queue_.pop();

    for (Edge &edge : vertices_[shortest_index].edges_from_this_vertex) {
      const int32_t neighbour_index = edge.connected_to;
      if (!vertices_[neighbour_index].distance_is_fixed) {
        const int32_t relative_distance = edge.weight;
        const int32_t distance_via_this_edge = shortest_distance + relative_distance;
        if (distance_via_this_edge < vertices_[neighbour_index].distance) {
          vertices_[neighbour_index].distance = distance_via_this_edge;
          priority_queue_.push(Pair(vertices_[neighbour_index].distance, neighbour_index));
        }
      }
    }
  }
}

void DijkstraAlgorithm::Print() noexcept {
  for (int32_t index = 0; index < number_of_vertices_; ++index) {
    std::cout << index << " " << vertices_[index].distance << std::endl;
  }
}

int main() {
  try {
    CallDijkstraAlgorithm(std::cin);
  } catch (...) {
    std::cerr << "ERROR: main()" << std::endl;
  }
  return 0;
}