Go: package main

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

//make priority queue
type Item struct {
	id       int
	priority int // this state is priority and distans from start
	index    int
}

type PriorityQueue []*Item

func (pq PriorityQueue) Len() int { return len(pq) }

// we want the ascending-priority-queue.
// So we use less than here.
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 = j
	pq[j].index = i
}

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
}

func (pq *PriorityQueue) update(dist int, id int) {
	for _, i := range *pq {
		if i.id == id {
			if i.priority > dist {
				i.priority = dist
			}
		}
	}
}

// the main code
func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())
	return n
}

func dikstra(dist [][]int, n int) []int {
	// preparate priority queue
	inf := 1 << 30
	pq := make(PriorityQueue, n)
	shortests := make([]int, n)
	for i := 0; i < n; i++ {
		pq[i] = &Item{
			id:       i,
			priority: inf,
			index:    i,
		}

		shortests[i] = inf
	}
	pq[0].priority = 0
	shortests[0] = 0

	for pq.Len() > 0 {
		item := heap.Pop(&pq).(*Item)
		shortests[item.id] = item.priority
		for id, d := range dist[item.id] {
			if d != -1 {
				pq.update(item.priority+d, id)
			}
		}
		heap.Init(&pq)
	}
	return shortests
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	// init
	n := nextInt(sc)
	dist := make([][]int, n)
	for i := 0; i < n; i++ {
		dist[i] = make([]int, n)
		for j := 0; j < n; j++ {
			dist[i][j] = -1
		}
	}

	// std Input
	for i := 0; i < n; i++ {
		u := nextInt(sc)
		k := nextInt(sc)
		for j := 0; j < k; j++ {
			v, c := nextInt(sc), nextInt(sc)
			dist[u][v] = c
		}
	}

	shortests := dikstra(dist, n)
	for i, d := range shortests {
		fmt.Printf("%d %d\n", i, d)
	}
}

C++: #include <functional>
#include <queue>
#include <stdio.h>
#include <utility>
#include <vector>

static const int MAX = 10000;
static const int INFINITY = 1 << 20;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;

static int n;
static std::vector<std::pair<int, int> > adj[MAX];

void dijkstra()
{
    std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int>>, std::greater<std::pair<int, int>> > PQ;
    int color[MAX];
    int d[MAX];

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

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

    while (!PQ.empty()) {
        std::pair<int, int> f = PQ.top();
        PQ.pop();
        int u = f.second;
        color[u] = BLACK;
    
        if (d[u] < f.first)
            continue;

        for (int i = 0; i < adj[u].size(); i++) {
            int v = adj[u][i].first;
            if (color[v] == BLACK)
                continue;
            if (d[v] > d[u] + adj[u][i].second) {
                d[v] = d[u] + adj[u][i].second;
                PQ.push(std::make_pair(d[v], v));
                color[v] = GRAY;
            }
        }
    }

    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i, (d[i] == INFINITY) ? -1 : d[i]);
    }
}

int main()
{
    scanf("%d", &n);
    
    for (int i = 0; i < n; i++) {
        int u, k;
        scanf("%d %d", &u, &k);
        for (int j = 0; j < k; j++) {
            int v, c;
            scanf("%d %d", &v, &c);
            adj[u].push_back(std::make_pair(v, c));
        }
    }
    
    dijkstra();
    return 0;
}

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

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


struct edge {
    int src;
    int dst;
    int weight;

    edge(int src, int dst, int w) : src(src), dst(dst), weight(w) {}
};

bool operator < (const edge &a, const edge &b) {
  return a.weight > b.weight;
}


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 (with pritority queue)
    vector<int> d(n, -1);
    vector<bool> visited(n, false);
    priority_queue<edge> Q;

    Q.push(edge(-1, 0, 0));
    while (!Q.empty()) {
        auto e = Q.top(); Q.pop();
        if (visited[e.dst])
            continue;
        d[e.dst] = e.weight;
        visited[e.dst] = true;

        int i = e.dst;
        int minw = numeric_limits<int>::max();
        for (int j = 0; j < n; ++j) {
            if (visited[j] || G[i][j] < 0)
                continue;
            int w = G[i][j] + d[i];
            Q.push(edge(i, j, w));
        }
    }

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

    return 0;
}

C++: #include <queue>
#include <stdint.h>
#include <vector>
#include <utility>
#include <array>
using namespace std;
typedef void (*single_source_shortest_path_callback_t)(int32_t index, int32_t weight);

#define GRAPH_MAX_SIZE 10000
enum color_t { WHITE, GRAY, BLACK };

static int32_t weights[GRAPH_MAX_SIZE];
static color_t colors[GRAPH_MAX_SIZE];

bool single_source_shortest_path(vector<pair<int32_t, int32_t>> *graph, size_t size, single_source_shortest_path_callback_t callback)
{
  if ((graph == nullptr) || (size == 0)) return false;

  int32_t i;
  for (i = 0; i < GRAPH_MAX_SIZE; i++) {
    weights[i] = INT32_MAX;
    colors[i] = WHITE;
  }

  weights[0] = 0;
  priority_queue<pair<int32_t, int32_t>> que;
  que.push(make_pair(-1 * weights[0], 0));

  while (!que.empty()) {
    pair<int, int> top = que.top();
    que.pop();
    int32_t top_index = top.second;
    int32_t top_weights = (-1) * top.first;
    if (top_weights > weights[top_index]) continue;

    callback(top_index, top_weights);
    colors[top_index] = BLACK;

    vector<pair<int32_t, int32_t>> vertex = graph[top_index];
    for (auto connect_to = vertex.begin(); connect_to != vertex.end(); connect_to++) {
      int32_t index = (*connect_to).first;
      if (colors[index] != BLACK) {
        int32_t new_weight = weights[top_index] + (*connect_to).second;

        if (new_weight < weights[index]) {
          weights[index] = new_weight;
          colors[index] = GRAY;
          que.push(make_pair(-1 * weights[index], index));
        }
      }
    }
  }
  return true;
}

#if !defined(TEST)
static vector<pair<int32_t, int32_t>> graph[GRAPH_MAX_SIZE];
static int32_t routes[GRAPH_MAX_SIZE];

void callback(int32_t index, int32_t weight)
{
  routes[index] = weight;
}

int32_t main(void)
{
  int32_t num;
  scanf("%d", &num);

  uint32_t i;
  for (i = 0; i < num; i++) {
    int32_t index, len;
    scanf("%d", &index);
    scanf("%d", &len);
    uint32_t j;
    for (j = 0; j < len; j++) {
      int32_t k, v;
      scanf("%d %d", &k, &v);
      graph[i].push_back(make_pair(k, v));
    }
  }
  single_source_shortest_path(graph, num, callback);

  for (i = 0; i < num; i++) {
    printf("%d %d\n", i, routes[i]);
  }

  return 0;
}
#endif