Go: package main

import (
	"bufio"
	"container/heap"
	"fmt"
	"os"
	"strconv"
)

const NIL = -1

type Node struct {
	id     int
	weight int
}

func init() {
	sc.Split(bufio.ScanWords)
}

type NodeHeap []Node

func (h NodeHeap) Len() int           { return len(h) }
func (h NodeHeap) Less(i, j int) bool { return h[i].weight < h[j].weight }
func (h NodeHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }

func (h *NodeHeap) Push(x interface{}) {
	*h = append(*h, x.(Node))
}

func (h *NodeHeap) Pop() interface{} {
	old := *h
	n := len(old)
	x := old[n-1]
	*h = old[0 : n-1]
	return x
}

var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func main() {
	n := scanInt()

	list := make([][]int, n)
	weight := make([]int, n)
	for i := range list {
		list[i] = make([]int, n)
		weight[i] = NIL
		for j := range list[i] {
			list[i][j] = NIL
		}
	}

	for i := 0; i < n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			v := scanInt()
			w := scanInt()
			list[u][v] = w
		}
	}

	start := Node{id: 0, weight: 0}
	h := &NodeHeap{start}
	heap.Init(h)

	for h.Len() > 0 {
		node := heap.Pop(h).(Node)
		if weight[node.id] != NIL {
			continue
		}
		weight[node.id] = node.weight

		for i, w := range list[node.id] {
			if w == NIL {
				continue
			}
			heap.Push(h, Node{id: i, weight: w + node.weight})
		}
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 0; i < n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, weight[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #include<bits/stdc++.h>
#define INF 1e9
#define MAX_V 100
using namespace std;
int cost[MAX_V][MAX_V];
int d[MAX_V];
bool used[MAX_V];
int V;
void dijkstra(int s){
    fill(d,d+V,INF);
    fill(used,used+V,false);
    d[s]=0;
    
    while(true){
        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]);
        }
    }
    
    for(int i=0;i<V;i++) cout<<i<<" "<<d[i]<<endl;

    return ;
}

int main(){
    cin>>V;
    int u,k,v,c;

    for(int i=0;i<V;i++)
        for(int j=0;j<V;j++) cost[i][j]=INF;
    
    for(int i=0;i<V;i++){
        cin>>u>>k;
        for(int j=0;j<k;j++){
            cin>>v>>c;
            cost[u][v]=c;
        }
    }
    
    dijkstra(0);
    
    return 0;
}

C++: #include<iostream>
#include<iomanip>
#include<queue>
#include<string>
#include<stack>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<cassert>
#include<ctime>
#include<algorithm>
#include<utility>
#include<map>
#include<set>
#include<vector>
#include<functional>

using namespace std;

#ifdef DEBUG
#define dprintf      printf
#define dout(x)      cout<<#x" = "<<(x)<<endl
#define darray(x,n)    {int i;rep(i,n)cout<<#x"["<<i<<"] = "<<*((x)+i)<<endl;}
#define dloop(i,s,g) for((i)=(s);(i)<(g);(i)++)
#define drep(i,n)    for((i)=0;(i)<(n);(i)++)
#define dstop()      scanf("%*c")
#else
#define dprintf      (1)?0:printf
#define dout(x)
#define darray(x,n)
#define dloop(i,s,g) if(1){}else
#define drep(i,n)    if(1){}else
#define dstop()      if(1){}else
#endif

#define F    first
#define S    second
#define pb   push_back
#define mp   make_pair

#define loop(i,s,g) for((i)=(s);(i)<(g);(i)++)
#define rep(i,n)    for((i)=0;(i)<(n);(i)++)
#define all(x)      (x.begin(),x.end())
#define in(T,...) T __VA_ARGS__; impl(__VA_ARGS__);
#define array(T,id,n) T id[n]; rep(i,n)cin>>id[i];

//#define int long long;
#ifndef int
#define INF  (0x7fffffff)
#else
#define LINF (0x7fffffffffffffff)
#endif

typedef long long           ll;
typedef unsigned            ui;
typedef unsigned long long  ull;
typedef pair<int,int>       i_i;
typedef pair<ll,int>        ll_i;
typedef pair<ll,ll>         ll_ll;
typedef pair<double,int>    d_i;
typedef pair<double,double> d_d;

void impl(){};
template <typename T,typename... TS >
void impl(T &head,TS &... tail)
{
  cin>>head;
  impl(tail ...);
}

typedef struct edge
{
  int to;
  int cost;
}Edge;
int V;
#define MAX_V (1000)
vector<Edge> G[MAX_V];
int d[MAX_V];

void djikstra(int s)
{
  int i;
  priority_queue<i_i,vector<i_i>,greater<i_i> > q;
  fill(d,d+V,INF);
  d[s]=0;
  q.push(i_i(0,s));
  while(!q.empty())
    {
      i_i p=q.top();
      q.pop();
      int v=p.S;
      if(d[v]<p.F)
	continue;
      rep(i,G[v].size())
	{
	  Edge e=G[v][i];
	  if(d[e.to]>d[v]+e.cost)
	    {
	      d[e.to]=d[v]+e.cost;
	      q.push(i_i(d[e.to],e.to));
	    }
	}
    }
}

signed main(void)
{
  int n;
  int i,j;
  int u;
  int k;
  Edge e;

  cin>>n;
  rep(i,n)
    {
      cin>>u>>k;
      rep(j,k)
	{ 
	  cin>>e.to>>e.cost;
	  G[j].pb(e);
	}
    }
  djikstra(0);
  rep(i,n)
    {
      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 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<iostream>
#include<vector>
#define INF (1<<21)
#define WHITE 1
#define BLACK 2
#define GRAY 3
#define neg -1
using namespace std;

int n;
int m[100][100];
vector<int> g;
vector<int> color;

void di(){
  int u, mincost;

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

  g[0] = 0;
  color[0] = GRAY;

  while(1){
    mincost = INF;
    u = -1;

    for(int i = 0; i < n; i++){
      if(mincost > g[i] && color[i] != BLACK){
	u = i;
	mincost = g[i];
      }
    }

    if(u == neg) break;

    color[u] = BLACK;

    for(int i = 0; i < n; i++){
      if(color[i] != BLACK && m[u][i] != INF){
	if(g[i] > (g[u] + m[u][i])){
	  g[i] = g[u] + m[u][i];
	  color[i] = GRAY;
	}
      }
    }
  }

  for(int i = 0; i < n; i++){
    cout << i << " " << (g[i] == INF ? neg:g[i]) << endl;

  }
}

int main()
{
  cin >> n;
  g.resize(n);
  color.resize(n);

  for(int i = 0; i < n; i++){
    for(int j = 0; j < n; j++){
      m[i][j] = INF;
    }
  }

  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;
    }
  }

  di();

  return 0;

}