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<cstdio>
#include<climits>
#include<cstring>
#include<algorithm>
#define INF 1<<25
using namespace std;
typedef long ull;
 
int main(){
  int n;
  int A[1000][1000];
  ull D[1000][1000];
  scanf("%d",&n);
  int u,k,C,V;
  
  for(int i=0;i<=n;i++){
    for(int j=0;j<=n;j++)D[i][j] = INF;
  }
  
  for(int i=0;i<n;i++){
    scanf("%d %d",&u,&k);    
    for(int j=0;j<k;j++){
      scanf("%d %d",&V,&C);
      D[u][V] = C;
      D[V][u] = C;
    }    
  }
  
  for(int i=0;i<n;i++)D[i][i] = 0;
  for(int k=0;k<n;k++)for(int i=0;i<n;i++)for(int j=0;j<n;j++)D[i][j] = min(D[i][j],D[i][k] + D[k][j]);
  for(int i=0;i<n;i++){
    cout << i << " " << D[0][i] << endl;
  }
  
  return 0;
}

C++: #include<iostream>
#include<algorithm>
#define inf 10000000
#define W 0
#define G 1
#define B 2
using namespace std;
int n,color[100];
int g[100][100],d[100],p[100];

void dikstr(int st){
int u,i,j;
	for(i=0;i<n;i++){
	color[i]=W;d[i]=inf;
	}
	d[st]=0;
	p[st]=-1;
	while(true){
	int mincost=inf;
		for(i=0;i<n;i++){
			if(color[i]!=B && d[i]<mincost){
			mincost=d[i];
				u=i;
			}
			
		}
		if(mincost==inf)
		break;
		color[u]=B;
		for(int v=0;v<n;v++){
			if(color[v]!=B && g[u][v]!=inf){
				if(d[u]+g[u][v]<d[v]){
				d[v]=d[u]+g[u][v];
					p[v]=u;
					color[v]=G;
				}
			}
		}
	}
}
main(){
	int i,j,u,k,c,v;
	cin>>n;
	for(i=0;i<n;i++){
		for(j=0;j<n;j++)
		g[i][j]=inf;
	}
	for(i=0;i<n;i++){
	cin>>u>>k;
		for(j=0;j<k;j++){
		cin>>v>>c;
			g[u][v]=c;
		}
	}
	dikstr(0);
	
	for(i=0;i<n;i++)
	cout<<i<<" "<<d[i]<<endl;
	return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
const int INF=1000000000;
int G[100][100];
int d[100],used[100];
int n;
void dijkstra(int s){
    fill(d,d+n,INF);
    fill(used,used+n,false);
    
    d[s]=0;
    while(true){
	int v=-1;
	for(int u=0;u<n;u++){
	    if(used[u]) continue;
	    if(v==-1||d[u]<d[v]) v=u;
	}
	if(v==-1) break;
	used[v]=true;

	for(int u=0;u<n;u++){
	    d[u]=min(d[u],d[v]+G[v][u]);
	}
    }
}
int main(){
    cin>>n;
    fill(G[0],G[n],INF);
    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]=G[v][u]=c;
	}
    }
    dijkstra(0);
    for(int i=0;i<n;i++){
	cout<<i<<" "<<d[i]<<endl;
    }

    return 0;
}

C++: #include<iostream>
using namespace std;
static const int MAX=100;
static const int INFTY=(1<<21);
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int n,M[MAX][MAX];

void dik(){
int min;
int d[MAX],color[MAX];

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

d[0]=0;
color[0]=GRAY;
while(1){
min=INFTY;
int u=-1;
for(int i=0;i<n;i++){
if(min>d[i]&&color[i]!=BLACK){
u=i;
min=d[i];
}
}
if(u==-1)break;
color[u]=BLACK;
for(int v=0;v<n;v++){
if(color[v]!=BLACK&&M[u][v]!=INFTY){
if(d[v]>d[u]+M[u][v]){
d[v]=d[u]+M[u][v];
color[v]=GRAY;
}
}
}
}
for(int i=0;i<n;i++){
cout << i <<" "<<(d[i]==INFTY ? -1 : d[i])<<endl;
}
}

int main(){
cin >> n;
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
M[i][j]=INFTY;
}
}

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

dik();

return 0;
}

C++: #include <stdio.h>
#include <queue>
using namespace std;
struct side{
    int to;
    int cost;
};
struct walk{
    int now;
    int cost;
};
int main(){
    int n,l,m,d[100];
    queue<walk> q;
    vector<side> map[100];
    walk temp,t;
    side s;
    scanf("%d",&n);
    for(int i=0;i<n;i++){
        scanf("%d%d",&l,&m);
        d[i]=-1;
        for(int j=0;j<m;j++){
            scanf("%d%d",&s.to,&s.cost);
            map[l].push_back(s);
        }
    }
    temp.now=temp.cost=0;
    q.push(temp);
    while(!q.empty()){
        temp=q.front();
        q.pop();
        if(d[temp.now]!=-1&&d[temp.now]<=temp.cost)continue;
        d[temp.now]=temp.cost;
        for(int i=0;i<map[temp.now].size();i++){
            t.cost=temp.cost+map[temp.now][i].cost;
            t.now=map[temp.now][i].to;
            q.push(t);
        }
    }
    for(int i=0;i<n;i++){
        printf("%d %d\n",i,d[i]);
    }
}

C++: #include <bits/stdc++.h>

using namespace std;

struct edge {
  int to, weight;
};

void dijkstra(vector<vector<edge>> graph, int start) {
  int n = graph.size();

  int dist[n];
  for (int i = 0; i < n; i++) {
    dist[i] = INT_MAX;
  }
  dist[start] = 0;

  priority_queue<pair<int, int>> que;
  que.push(make_pair(dist[start], start));
  while (!que.empty()) {
    int v = que.top().second;
    int c = que.top().first;
    que.pop();
    for (int i = 0; i < graph[v].size(); i++) {
      edge e = graph[v][i];
      if (dist[e.to] > c + e.weight) {
        dist[e.to] = c + e.weight;
        que.push(make_pair(dist[e.to], e.to));
      }
    }
  }

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

int main() {
  int n;
  cin >> n;
  vector<vector<edge>> graph;
  graph.resize(n);
  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;
      graph[u].emplace_back(edge{v, c});
    }
  }

  dijkstra(graph, 0);
}