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 <bits/stdc++.h>
using namespace std;
static const int INF   = (1 << 21);
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int NIL   = -1;
static const int MAX   = 10000;

int n;
vector<vector<pair<int, int>>> M(MAX);

void dijstra(int s) {
  vector<int> color(n, WHITE);
  vector<int> d(n, INF);
  d[s] = 0;
  priority_queue<pair<int, int>> pq;
  pq.push(make_pair(0, 0));

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

    int u    = tmp.second;
    color[u] = BLACK;
    if (d[u] < tmp.first * (-1)) continue;

    int size = M[u].size();
    for (int i = 0; i < size; i++) {
      int v = M[u][i].second;
      if (color[v] == BLACK) continue;

      if (d[u] + M[u][i].first < d[v]) {
        d[v]     = d[u] + M[u][i].first;
        color[v] = GRAY;
        pq.push(make_pair(d[v] * (-1), v));
      }
    }
  }
  int res = 0;
  for (int i = 0; i < n; i++) {
    cout << i << " " << d[i] << endl;
  }
}

int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    int id, k;
    cin >> id >> k;
    for (int j = 0; j < k * 2; j += 2) {
      pair<int, int> p;
      cin >> p.second >> p.first;
      M[id].push_back(p);
    }
  }
  dijstra(0);
}

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;
}