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++: #define RangeFor(i,n) for(int i=0; i<n; ++i)
#define RvRngFor(i,n) for(int i=n-1; i>=0; --i)

#include <iostream>
#include <vector>
#include <queue>
#include <utility>
#include <numeric>

using std::vector;
using std::cin;
using std::priority_queue;
using std::pair;
using std::make_pair;


vector<int> sssp(vector<vector<pair<int, int> > > c, int start_node = 0){
    int n = c.size();
    priority_queue<pair<int, int>, vector<pair<int,int> >, std::greater<pair<int, int>> > pq;
    vector<int> temp_dist(n, std::numeric_limits<int>::max());
    pq.push(make_pair(0, start_node));

    for(;!pq.empty();pq.pop()){
        auto t = pq.top();
        auto d = t.first;
        auto u = t.second;


        if(d < temp_dist[u]){
            temp_dist[u] = d;
            auto k = c[u].size();
            RangeFor(j, k) {
                pq.push(make_pair(d + c[u][j].second, c[u][j].first));
            }
        }
    }

    return temp_dist;
}

int main(){
    int n; cin >> n;
    vector<vector< pair<int,int> > > c(n);
    RangeFor(i, n) {
        int u;
        cin >> u;
        int k;
        cin >> k;
        c[u] = vector<pair<int, int> >(k);
        RangeFor(j, k) {
            int v;
            cin >> v;
            int d;
            cin >> d;
            c[u][j] = make_pair(v, d);
        }
    }

//    RangeFor(i, n){
//        RangeFor(j, c[i].size()){
//            std::cout << c[i][j].first << ' ' << c[i][j].second;
//        }
//        std::cout << std::endl;
//    }
    
    auto res = sssp(c);
    RangeFor(i, n){
        std::cout << i << ' ' << res[i] << std::endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cassert>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define rep(i,n) FOR(i,0,n)
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define vint vector<int>
#define vdouble vector<double>
#define vstring vector<string>
using namespace std;

#include<map>
#include<set>
#include<queue>

typedef long long ll;
typedef unsigned long long ull;

const int MAX_N = 1000000;
const int INFTY = (1 << 21); // 2097152
// const ll INFTY = (1 << 60);

class Edge{
public:
	int from, to, cost;
	Edge(int from = 0, int to = 0, int cost = 0) :
			from(from), to(to), cost(cost){}

	bool operator < (const Edge &e) const{
		return cost < e.cost;
	}
	bool operator >(const Edge &e) const{
		return cost > e.cost;
	}

};

class Node{
public:
	vector<Edge> edges;
	int dist;

	Node(){
		dist = INFTY;
	}
};

class Graph{
public:
	vector<Node> nodes;
	Graph(int n) {
		rep(i, n) { Node n;  nodes.push_back(n); }
	}
	Node& operator[](int i){
		return nodes[i];
	}
};

class Data{

public:
	int dist;
	Edge *edge;
	Data(int dist, Edge *edge) {
		this->dist = dist;
		this->edge = edge;
	}

	bool operator < (const Data &d) const{
		return dist < d.dist;
	}
	bool operator >(const Data &d) const{
		return dist > d.dist;
	}
};

Graph G(0);
int N;

void dijkstra(){

    priority_queue<Data, vector<Data>, greater<Data>> pq;
    Edge e0 = Edge(-1, 0, 0);
    Data d0 = Data(0, &e0);
    pq.push(d0);

    while(!pq.empty()){
        Data d = pq.top(); pq.pop();
        Edge &e = *d.edge;
        Node &n = G[e.to];
        if(n.dist <= d.dist) continue;
        n.dist = d.dist;
        // cerr << n.dist << endl;

        for(auto &ee: n.edges){
            pq.push(Data(n.dist + ee.cost, &ee));
        }
    }

}

int main() {
	cin >> N;
	G = Graph(N);

    rep(i, N){
        int from; cin >> from;
        int NN; cin >> NN;
        rep(i, NN){
            int to, cost;
            cin >> to >> cost;
            G[from].edges.push_back(Edge(from, to, cost));
        }
    }

    dijkstra();
    rep(i, N){
        cout << i << " " << G[i].dist << endl;
    }
}

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

using namespace std;

static const int MAX = 10000;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

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

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

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

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

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

    color[u] = BLACK;

    for (int j = 0; j < adj[u].size(); j++) {
      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;
      }
    }
  }

  for (int i = 0; i < n; i++) {
    cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
  }
}

int main() {
  cin >> n;

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

  dijkstra();

  return 0;
}