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<vector>
#include<queue>
using namespace std;
#define MAX 10000
#define INF 1 << 30

int n, d[MAX];
vector<pair<int, int> > V[MAX];
bool vis[MAX];

void dijkstra(int s){
  for ( int i = 0; i < n; i++)d[i] = INF;
  for ( int i = 0; i < n; i++){ vis[i] = false; }
  d[s] = 0;
  priority_queue<pair<int, int> > PQ;
  PQ.push(make_pair(0, s));
  while ( !PQ.empty() ){
    s = PQ.top().second; PQ.pop();
    if ( vis[s] ) continue;
    vis[s] = true;
    for ( int i = 0; i < V[s].size(); i++){
      pair<int, int> f = V[s][i];
      int v = f.first;
      int c = f.second;
      if (!vis[v] && d[v] > d[s] + c ){
        d[v] = d[s] + c;
        PQ.push(make_pair((-1) * d[v], v));
      }
    }
  }
}

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;
      V[u].push_back(make_pair(v, c));
    }
  }

  dijkstra(0);

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

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
static const int MAX = 10000;
static const int INFTY = (1 << 20);
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;

    // 最小値を取り出し、それが最短でなければ無視
    if (d[u] < f.first * (-1))
    {
      continue;
    }

    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;
        // priority_queueはデフォルトで大きい値を優先するため-1を掛ける
        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()
{
  int k, u, v, c;

  cin >> n;
  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;
}

C++: #define _CRT_SECURE_NO_WARNINGS
// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define range(i,a,b) for(int i = a; i < (int)(b); i++)
#define rep(i,b) range(i,0,b)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define mt make_tuple
using ll = long long;
// #define int ll
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int,int>;
void fastios(){ ios_base::sync_with_stdio(0); cin.tie(0); }
int const mod = 1000000007;
auto const inf = numeric_limits<int>::max()/8;

using Weight = int;
using Capacity = int;
struct Edge {
    int src, dst; Weight weight;
    Edge(int s, int d, int w) : src(s), dst(d), weight(w) {}
};
using Edges = vector<Edge>;
using Graph = vector<Edges>;
using Array = vector<Weight>;
using Matrix = vector<Array>;

pair<vector<Weight>, bool> spfa(const Graph &g, int s){
    const Weight inf = numeric_limits<Weight>::max()/4;
    const int n = g.size(); queue<int> q;
    vector<Weight> dist(n, inf); vector<int> inQ(n);
    vector<int> count(n);
    dist[s] = 0; q.emplace(s); inQ[s] = true; ++count[s];
    bool negCycle = false;
    while(q.size()){
        int v = q.front(); q.pop(); inQ[v] = false;
        for(auto &e : g[v]){
            if(dist[v] != inf && dist[e.dst] > dist[v] + e.weight){
                dist[e.dst] = dist[v] + e.weight;
                if(!inQ[e.dst]){
                    q.emplace(e.dst); inQ[e.dst] = true; ++count[e.dst];
                    if(count[e.dst] >= n){ negCycle = true; goto END; }
                }
            }
        }
    }
 END:;
    return make_pair(dist, !negCycle);
}

int main(){
    fastios();
    int n;
    cin >> n;
    Graph g(n);
    rep(i,n){
        int u,k;
        cin >> u >> k;
        rep(j,k){
            int v,c;
            cin >> v >> c;
            g[u].eb(u,v,c);
        }
    }
    auto dist = spfa(g,0);
    rep(i,n){
        cout << i << ' ' << get<0>(dist)[i] << '\n';
    }
}

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>

using namespace std;

#define MAX_N 100
#define INF 100000 * 100 + 1

int cost[MAX_N][MAX_N];
int d[MAX_N];
bool used[MAX_N];
int V;

void dijkstra(int s) {
	fill_n(d, V, INF);
	fill_n(used, V, false);
	d[s] = 0;

	while (1) {
		int v = -1;
		for (int u = 0; u < V; u++)
			if (!used[u] && (v == -1 || d[u] < d[v]))
				v = u;

		if (v == -1)
			break;

		used[v] = true;

		for (int u = 0; u < V; u++)
			d[u] = min(d[u], d[v] + cost[v][u]);
	}
}

int main() {
	int n;
	cin >> n;
	V = n;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		fill_n(cost[u], n, INF);
		for (int j = 0; j < k; j++) {
			int v, c;
			cin >> v >> c;
			cost[u][v] = c;
		}
	}
	dijkstra(0);
	for (int i = 0; i < n; i++) {
		cout << i << " " << d[i] << endl;
	}
	
	return 0;
}