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 <cstdio>
#include <vector>
#include <queue>
using namespace std;
const int MAXN = 1e4 + 7, INF = 5e5 + 7;
int d[MAXN];
struct node {
	int id, dist;
	node(int id, int dist) :id(id), dist(dist) {}
	bool operator < (const node &rhs) const {
		return dist > rhs.dist;
	}
};
vector<pair<int, int> > G[MAXN];
priority_queue<node> nodes;
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 1; i < n; i++) {
    	d[i] = INF;
	}
    for (int i = 0; i < n; i++) {
    	int u, k;
    	scanf("%d%d", &u, &k);
    	for (int j = 0; j < k; j++) {
    		int v, c;
    		scanf("%d%d", &v, &c);
    		G[u].push_back(make_pair(v, c));
		}
	}
	nodes.push(node(0, 0));
	while (!nodes.empty()) {
		node tmp = nodes.top();
		nodes.pop();
		if (tmp.dist > d[tmp.id]) continue;
		int cnt = G[tmp.id].size();
		for (int i = 0; i < cnt; i++) {
			if (d[G[tmp.id][i].first] > d[tmp.id] + G[tmp.id][i].second) {
				d[G[tmp.id][i].first] = d[tmp.id] + G[tmp.id][i].second;
				nodes.push(node(G[tmp.id][i].first, d[G[tmp.id][i].first]));
			}
		}
	}
	for (int i = 0; i < n; i++) {
		printf("%d %d\n", i, d[i]);
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
static const int INFTY = (1 << 21);

int n,M[100][100];

void dikstra(){
  int u,minu,d[100],p[100],color[100];
  for (int i = 0; i < n; i++) {
    color[i] = 0;
    d[i] = INFTY;
  }
  d[0] = 0;
  color[0] = 1;

  while (1) {
    minu = INFTY;
    u = -1;
    for (int i = 0; i < n; i++) {
      if (color[i] != 2 && d[i] < minu) {
        minu = d[i];
        u = i;
      }
    }
    if (u == -1)break;
    color[u] = 2;

    for (int v = 0; v < n; v++) {
      if (color[v] != 2 && M[u][v] != INFTY) {
        if (d[u] + M[u][v] < d[v]) {
          d[v] = d[u] + M[u][v];
          color[v] = 1;
        }
      }
    }
  }
  for (int i = 0; i < n; i++) {
    cout << i << " " <<(d[i] == INFTY ? -1 : d[i])<< endl;
  }

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

  dikstra();

  return 0;
}

C++: #include<stdio.h>
#include<algorithm>
#include<iostream>
using namespace std;
#define INF 1<<21
int main()
{
	long long int min,n,u,k,v,c,dist[100][100],s,cost[100],t[100],l=1;
	cin>>n;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<n;j++)
		{
			dist[i][j]=INF;
			cost[i]=INF;
			t[i]=-1;
		}
	}
	min=INF;
	dist[0][0]=0;
	for(int i=1;i<=n;i++)
	{
		cin>>u;
		cin>>k;
		for(int i=1;i<=k;i++)
		{
			cin>>v>>c;
			dist[u][v]=c;
		}
	}
	s=0;
	cost[s]=0;
	while(l!=n)
	{
		for(int i=0;i<n;i++)
		{
			if(dist[s][i]!=INF)
			{
				if(cost[s]+dist[s][i]<cost[i])
				{
					cost[i]=cost[s]+dist[s][i];
				}
				
			}
		}
		t[s]=1;
		for(int i=1;i<n;i++)
		{
			if(cost[i]<min&&t[i]==-1)
			{
				min=cost[i];
				s=i;
			}
		}
		min=INF+1;
		l++;
	}
	for(int i=0;i<n;i++)
	{
		cout<<i<<" "<<cost[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 dijkstra(){
  int minv;
  int d[MAX],color[MAX];
  for(int i=0;i<n;i++){
    d[i]=INFTY;
    color[i]=WHITE;
  }
  d[0]=0;
  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;
}