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>
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 dijkstra(){
  int minv;
  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){
    minv=INFTY;
    int u=-1;
    for(int i=0;i<n;i++){
      if(minv>d[i]&&color[i]!=BLACK){
	u=i;
	minv=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;
    }
  }

  dijkstra();

  return 0;
}

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

typedef long long ll;

using namespace std;

int n;
int G[10010][10010];
int minlen[10010];
bool vis[10010];


void dijkstra(int p){
	memset(minlen,-1,sizeof(minlen));
	memset(vis,0,sizeof(0));
	
	minlen[p] = 0;
	
	while (1){
		int minp = -1;
		int minn = 1<<30;
	
		for(int i = 0 ; i<n ; i++){
			if(!vis[i] && minlen[i]!=-1 && minn>minlen[i]){
				minp = i;
				minn = minlen[i];
			}
		}
		if(minp == -1) break;
		
		vis[minp] = 1;
		for(int j = 0 ; j<n ; j++){
			if(!vis[j] && G[minp][j]!=1<<30){
				if(minlen[j] == -1){
					minlen[j] = minlen[minp]+G[minp][j];
				}
				else if( minlen[j] > minlen[minp]+G[minp][j]){
					minlen[j] = minlen[minp]+G[minp][j];
				}
			}
		}
	}
}

int main(){
	ios::sync_with_stdio(false);
	cin>>n;
	for(int i = 0 ; i<n ; i++)
		for(int j = 0 ; j<n ; j++)
			G[i][j] = 1<<30;
	
	for(int t = 0 ; t<n ; t++){
		int u,k;
		cin>>u>>k;
		for(int i = 0 ; i<k ; i++){
			int to,weight;
			cin>>to>>weight;
			G[u][to] = weight;
		}
	}

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

C++: #include <iostream>
using namespace std;
static const int MAX=101;
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 dijkstra(){
    int minv;
    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){
        minv=INFTY;
        int u=-1;
        for(int i=0;i<n;i++){
            if(minv>d[i] && color[i]!=BLACK){
                u=i;
                minv=d[i];
            }
        }
        if(u==-1) break;
        color[u] = BLACK;
        for(int i=0;i<n;i++){
            if(color[i]!=BLACK && M[u][i]!=INFTY){
                if(d[i]>M[u][i]+d[u]){
                    d[i]=M[u][i]+d[u];
                    color[i]=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;
        }
    }
    
    for(int i=0;i<n;i++){
        int x,y;cin >> x >> y;
        for(int j=0;j<y;j++){
            int z;cin >> z;
            cin >> M[x][z];
        }
    }
    
    dijkstra();
    
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <limits>
#include <queue>
#include <map>
#include <ctime>

using namespace std;

#define rip(i,n,s) for (int i=(s);i<(int)(n);i++)
#define all(a) (a).begin(),(a).end()
typedef pair<long long,int> P;
int main(){
    int n;
    cin >> n;
    vector<vector<P> > da(n,vector<P>(0));
    rip(i,n,0){
        int u,k;
        cin >> u >> k;
        rip(j,k,0){
            long long c;
            int v;
            cin >> v >> c;
            da[u].push_back(make_pair(c,v));
        }
    }
    priority_queue<P,vector<P>,greater<P> > q;
    vector<long long> ans(n,0);
    rip(i,da[0].size(),0){
        q.push(da[0][i]);
    }
    while (!q.empty()){
        P x=q.top();
        q.pop();
        if(ans[x.second]==0 && x.second!=0){
            ans[x.second]=x.first;
            rip(i,da[x.second].size(),0){
                q.push(make_pair(x.first+da[x.second][i].first,da[x.second][i].second));
            }
        }
    }
    rip(i,n,0){
        cout << i << ' ' << ans[i] << endl;
    }
}

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

#define MAX 100
#define INF INT_MAX
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n;
int col[MAX];
int M[MAX][MAX];
int d[MAX];
int p[MAX];

void init(int n) {
	for (int i = 0; i < n; i++) {
		col[i] = WHITE;
		for (int j = 0; j < n; j++)
			M[i][j] = INF;
		d[i] = INF;
	}
}

void input() {
	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;
			M[i][v] = c;
		}
	}
}

void dijkstra(int s) {
	d[s] = 0;
	p[s] = -1;
	while (true) {
		int minc = INF;
		int u;
		for (int i = 0; i < n; i++) {
			if (col[i] != BLACK && d[i] < minc) {
				minc = d[i];
				u = i;
			}
		}
		if (minc == INF) break;
		col[u] = BLACK;
		for (int v = 0; v < n; v++) {
			if (col[v] != BLACK && M[u][v] != INF) {
				if (d[u] + M[u][v] < d[v]) {
					d[v] = d[u] + M[u][v];
					p[v] = u;
					col[v] = GRAY;
				}
			}
		}
	}
}

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

int main() {
	cin >> n;
	init(n);
	input();
	dijkstra(0);
	output();
	return 0;
}