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 <iostream>
#include <queue>
#include <utility>
#include <vector>
using namespace std;

const int MAX_N = 100;
const int INF = (1 << 21);

int N;
vector<pair<int, int> > A[MAX_N];

void dj() {
  int d[MAX_N], c[MAX_N];

  // (first: distance*-1, second: adjacent)
  priority_queue<pair<int, int> > PQ; 

  for (int i = 0; i < N; i++) {
    d[i] = INF;
    c[i] = -1;
  }

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

  while (!PQ.empty()) {
    pair<int, int> t = PQ.top(); PQ.pop();
    int cur_n = t.second;
    c[cur_n] = 1;

    if (d[cur_n] < t.first * -1) continue;

    for (int i = 0; i < A[cur_n].size(); i++) {
      int adj_n = A[cur_n][i].first;

      if (c[adj_n] == 1) continue;

      if (d[cur_n] + A[cur_n][i].second < d[adj_n]) {
        d[adj_n] = d[cur_n] + A[cur_n][i].second;
        PQ.push(make_pair(d[adj_n] * -1, adj_n));
        c[adj_n] = 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 cur_n, k; cin >> cur_n >> k;

    for (int j = 0; j < k; j++) {
      int u, v; cin >> u >> v;
      A[cur_n].push_back(make_pair(u, v));
    }
  }

  dj();

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;

static const int N = 10000;
static const int inf = (1 << 30);
static const int white = 0;
static const int gray = 1;
static const int black = 2;

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

void dijkstra(int s) {
	int color[N], d[N];
	for (int i = 0; i < n; i++) {
		color[i] = white;
		d[i] = inf;
	}
	priority_queue<pair<int, int> > PQ;
	d[s] = 0;
	color[s] = gray;
	PQ.push(make_pair(s, 0));
	while (!PQ.empty()) {
		pair <int, int> f = PQ.top();
		PQ.pop();
		int u = f.second;
		color[u] = black;
		for (int k = 0; k < adj[u].size(); k++) {
			int v = adj[u][k].first;
			if (color[v] == black)
				continue;
			if (d[v] > d[u] + adj[u][k].second) {
				d[v] = d[u] + adj[u][k].second;
				PQ.push(make_pair(d[v] * (-1), v));
				color[v] = gray;
			}
		}
	}
	for (int i = 0; i < n; i++) {
		if (d[i] == inf) {
			cout << i << " " << -1 << '\n';
		} else {
			cout << i << " " << d[i] << '\n';
		}
	}
}
int main() {
	cin >> n;
	int u, k, 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(0);
	return 0;
}

C++: #include <bits/stdc++.h>
 
using namespace std;
 
#define FOR(i,s,e) for((i)=(s);(i)<(int)(e);(i)++)
#define REP(i,e) FOR(i,0,e)
 
#define all(o) (o).begin(), (o).end()
#define psb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
 
typedef long long ll;
typedef pair<int, int> PII;
 
const double EPS = 1e-10;
 
typedef struct edge_def {
  int from;
  int to;
  int cost;
 
  edge_def(int _from, int _to, int _cost) {
    from = _from;
    to   = _to;
    cost = _cost;
  }
} edge;
 
const int INF = INT_MAX;
const int V = 10000;
int n, t;
vector<edge> es[V];
int d[V];
 
void dijkstra(int s) {
  int i;
  priority_queue<PII, vector<PII>, greater<PII > > q;
  for (i=0; i<n; i++) d[i] = INF;
  d[s] = 0;
  q.push(PII(0, s));
 
  while (q.size()) {
    PII p = q.top();
    q.pop();
    int v = p.second;
 
    if (d[v] < p.first) continue;
 
    for (i=0; i<(int)es[v].size(); i++) {
      edge e = es[v][i];
      if (d[e.to] > d[v] + e.cost) {
        d[e.to] = d[v] + e.cost; 
        q.push(PII(d[e.to], e.to));
      }
    }
  }
}
 
int main() {
  int i, j, k;
  int u, v, c;
  for (i=0; i<V; i++) es[i].clear();
 
  scanf("%d ", &n);
  for (i=0; i<n; i++) {
    scanf("%d%d ", &u, &k);
    for (j=0; j<k; j++) {
      scanf("%d%d ", &v, &c);
      es[u].psb(edge(u, v, c));
    }
  }
 
  dijkstra(0);
 
  for (i=0; i<n; i++) {
    printf("%d %d\n", i, d[i]);
  }
 
    return 0;
}

C++: #include<iostream>
#include<cstdio>
#define INFTY 2000000001
#define LEN 1000000
using namespace std;
struct edge {
  int from,to,cost,k;
};
edge es[LEN];
int main(){
  int n,u,k,E,c,v;
  int d[LEN];
  E = 0;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++){
      cin>>v>>c;
      es[E].from = u;
      es[E].to = v;
      es[E++].cost = c;
    }
  }
  for(int i=0;i<n;i++)d[i] = INFTY;
  d[0] = 0;
  while(true){
    bool update = false;
    for(int i=0;i<E;i++){
      edge e = es[i];
      if(d[e.from] != INFTY && d[e.to] > d[e.from] + e.cost){
    d[e.to] = d[e.from] + e.cost;
    update = true;
      }
    }
    if(update==false)break;
  }
  for(int i=0;i<n;i++)cout << i << " " << d[i] << endl;
  return 0;
}