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 <bits/stdc++.h>
using namespace std;

#define rep(i, n) for (int i=0; i<(n); ++i)
using ll = long long;
using P = pair<int, int>;

const int INF = 1 << 21;
const int MAX = 10003;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
int n;
vector<P> adj[MAX];

void dijkstra() {
  priority_queue<P> PQ;
  int color[MAX], d[MAX];

  fill((int*)d, (int*)(d+MAX), INF);
  fill((int*)color, (int*)(color+MAX), WHITE);

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

  while (!PQ.empty()) {
    P f = PQ.top(); PQ.pop();
    int u = f.second;
    color[u] = BLACK;

    if (d[u] < f.first * (-1)) continue;

    rep(j, adj[u].size()) {
      int v = adj[u][j].first;
      if (color[v] == BLACK) continue;
      if (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] = GRAY;
      }
    }
  }

  rep(i,n) {
    cout << i << ' ' << (d[i] == INF ? -1 : d[i]) << endl;
  }
}

int main() {
  cin >> n;  
  int u, k, v, c;
  rep(i,n) {
    cin >> u >> k;
    rep(j,k) {
      cin >> v >> c;
      adj[u].push_back(make_pair(v, c));
    }
  }

  dijkstra();
  return 0;
}

C++: #include <stdio.h>
#include <stdint.h>
#include <iostream>
#include <fstream>
#include <cassert>
#include <climits>

#include <memory>
#include <queue>
using namespace std;

#define DEBUG (0)

#if DEBUG
#define DPRINTF(...) do { \
    printf("D(L%d) %s: ", __LINE__, __func__); \
    printf(__VA_ARGS__); \
  } while (false)
#else
#define DPRINTF(...)
#endif // DEBUG


const int kMaxVertex = 10000;
int g_num_of_vertex;
int g_min_weight[kMaxVertex];

struct Edge {
    Edge(int num_vertex)
        : num_vertex_(num_vertex)
    {
        const int size_of_ptr_ = num_vertex_ * num_vertex_;
        weight_ = unique_ptr<int>(new int[size_of_ptr_]);

        for (int i = 0; i < num_vertex_; i++)
            for (int j = 0; j < num_vertex_; j++)
                setWeight(i, j, kInvalidWeight);

        for (int i = 0; i < num_vertex_; i++)
            setWeight(i, i, 0);
    }

    const int kInvalidWeight = INT_MAX;

    bool isConnected(int v0, int v1) const;
    vector<int> getConnectedVertices(int v) const;
    int getWeight(int v0, int v1) const;
    void setWeight(int v0, int v1, int w);

    void printWeight() const;

    int num_vertex_;
    int size_of_ptr_;
    unique_ptr<int> weight_;
};

bool Edge::isConnected(int v0, int v1) const
{
    if (v0 == v1)
        return false;

    if (getWeight(v0, v1) == kInvalidWeight)
        return false;

    return true;
}

vector<int> Edge::getConnectedVertices(int v) const
{
    vector<int> vertices;

    for (int i = 0; i < num_vertex_; i++)
        if (isConnected(v, i))
            vertices.push_back(i);

    return vertices;
}

void Edge::setWeight(int v0, int v1, int w)
{
    assert(0 <= v0 && v0 < num_vertex_);
    assert(0 <= v1 && v1 < num_vertex_);

    int *p = weight_.get() + (v0 * num_vertex_) + v1;
    *p = w;
}

int Edge::getWeight(int v0, int v1) const
{
    int *p = weight_.get() + (v0 * num_vertex_) + v1;
    return *p;
}

void Edge::printWeight() const
{
    DPRINTF("\n");
    for (int i = 0; i < num_vertex_; i++)
    {
        printf("    [%d]", i);
        for (int j = 0; j < num_vertex_; j++)
        {
            const int w = getWeight(i, j);
            if (w != kInvalidWeight)
                printf(" %d", getWeight(i, j));
            else
                printf(" -");
        }
        cout << endl;
    }
}


struct VtxAndWeight {
    VtxAndWeight(int vtx, int weight)
        : vtx_(vtx)
        , weight_(weight)
    {}

    int vtx_;
    int weight_;

    bool operator>(const VtxAndWeight& rhs)
    {
        return (*this).weight_ > rhs.weight_;
    };

    bool operator<(const VtxAndWeight& rhs)
    {
        return (*this).weight_ < rhs.weight_;
    };
};

struct LessThanByWeight
{
    bool operator()(const VtxAndWeight& lhs, const VtxAndWeight& rhs) const
    {
        return lhs.weight_ > rhs.weight_;
    }

};


/* Dijkstra's algorithm */
void calcShortestPath(int start, const Edge &edge)
{
    priority_queue<VtxAndWeight, vector<VtxAndWeight>, LessThanByWeight> priority_queue;

    const int init_weight = 0;
    g_min_weight[start] = 0;
    priority_queue.push(VtxAndWeight(start, init_weight));

    while (!priority_queue.empty())
    {
        // select the minimum weight from the priority queue
        const int vtx = priority_queue.top().vtx_;
        const int weight = priority_queue.top().weight_;
        priority_queue.pop();

        DPRINTF("vtx %d  weight %d\n", vtx, weight);

        if (weight > g_min_weight[vtx])
            continue;

        // find connected vertices
        vector<int> connectedVertices = edge.getConnectedVertices(vtx);

        // update min weight for the vertices
        for (int neighbour : connectedVertices)
        {
            const int updated_weight= weight + edge.getWeight(vtx, neighbour);

            if (updated_weight < g_min_weight[neighbour])
            {
                g_min_weight[neighbour] = updated_weight;
                priority_queue.push(VtxAndWeight(neighbour, g_min_weight[neighbour]));
            }

            DPRINTF("g_min_weight[%d] %d\n", neighbour, g_min_weight[neighbour]);
        }
    }

}


int main()
{
    cin >> g_num_of_vertex;
    cin.ignore();

    assert(kMaxVertex > g_num_of_vertex);

    // init
    for (int i = 0; i < g_num_of_vertex; i++)
    {
        g_min_weight[i] = INT_MAX;
    }

    Edge edge(g_num_of_vertex);

    // input
    for (int i = 0; i < g_num_of_vertex; i++)
    {
        int start, degree;
        cin >> start >> degree;

        for (int j = 0; j < degree; j++)
        {
            int dst, weight;
            cin >> dst >> weight;

            edge.setWeight(start, dst, weight);
        }

        cin.ignore();
    }

#if DEBUG
    edge.printWeight();
#endif

    // process
    const int start = 0;
    calcShortestPath(start, edge);

    // output
    for (int i = 0; i < g_num_of_vertex; i++)
        printf("%d %d\n", i, g_min_weight[i]);

    return 0;
}