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<cstdio>
#include<iostream>
#define INF 200001 
 
int main(){
 int u,k,C,V,A[1000][1000],D[1000][1000],n;
  scanf("%d",&n);
   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;
      }    
  }
  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++)printf("%d %d\n",i,D[0][i]);
  return 0;
}

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

typedef pair<int, int> P;

struct Edge {
  int to, cost;
};

int n;
vector<vector<Edge> > G;

vector<int> dij() {
  priority_queue<P, vector<P>, greater<P> > Q;
  vector<int> d(n, -1);
  Q.push({0, 0});
  while ( !Q.empty() ) {
    P p = Q.top(); Q.pop();
    int v = p.second, c = p.first;

    if ( d[v] >= 0 ) continue;
    d[v] = c;
    
    for ( Edge e: G[v] ) {
      Q.push({c+e.cost, e.to});
    }    
  }

  return d;
}

int main() {
  cin >> n;

  G = vector<vector<Edge> >(n);
  for ( int i = 0; i < n; i++ ) {
    int u, k;
    cin >> u >> k;
    for ( int i = 0; i < k; i++ ) {
      int v, c;
      cin >> v >> c;
      G[u].push_back({v, c});      
    }
  }

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

C++: #include <iostream>

using namespace std;


static const int white = 0;
static const int black = 1;
static const int emp = -1;
static const int inf = 1000000;

int graph[124][124] = {{}};
int d[124] = {};
int n;



void dijkstra(){

  int u,mincost;
  int p[124] = {};
  int color[124] = {};

  for(int i = 0;i < n;i++){
    d[i] = inf;
    color[i] = white;
    p[i] = emp;
  }

  d[0] = 0;

  while(1){

    mincost = inf;
    for(int i = 0;i < n;i++){
      if(color[i] != black && mincost > d[i]){
	mincost = d[i];
	u = i;
      }
    }
    //  cout << "u =  " << u << endl;

    if(mincost == inf) break;
    color[u] = black;

    for(int i = 0;i < n;i++){
      if(color[i] != black && graph[u][i] != emp){
	if(d[u] + graph[u][i] < d[i]){
	  d[i] = d[u] + graph[u][i];
	  p[i] = u;
	}
      }
    }
  }
}


int main(){

  int u,k,ui,c;
  cin >> n;



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


  for(int i = 0;i < n;i++){

    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> ui >> c;
      graph[u][ui] = c;
    }
  }


  dijkstra();

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

}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <climits>

struct Node {
	int id;
	std::vector<int> edge_to;
	std::vector<int> edge_cost;
	bool done;
	int cost;
};

int min(int x, int y)
{
	return x>y ? y : x;
}

void insert(Node* nodes, std::vector<int>& q, int t)
{
	std::vector<int>::iterator it = q.begin();
	for (; it != q.end(); ++it) {
		if (nodes[*it].id == nodes[t].id) return;
		if (nodes[*it].cost > nodes[t].cost) break;
	}
	q.insert(it, t);
}

int main()
{
	int n; std::cin >> n;
	
	Node* nodes = new Node[n];
	
	for (int i=0; i<n; i++) {
		nodes[i].done = false;
		nodes[i].cost = INT_MAX;
	}
	
	for (int i=0; i<n; i++) {
		int id, deg;
		std::cin >> id >> deg;
		nodes[i].id = id;
		for (int j=0; j<deg; j++) {
			int t, cost;
			std::cin >> t >> cost;
			nodes[i].edge_to.push_back(t);
			nodes[i].edge_cost.push_back(cost);
		}
	}
	
	std::vector<int> que;
	que.push_back(0);
	nodes[0].cost = 0;
	
	while (!que.empty()) {
		int s = que[0]; que.erase(que.begin());
		nodes[s].done = true;
		for (int k=0; k<nodes[s].edge_to.size(); k++) {
			int t = nodes[s].edge_to[k];
			int cost = nodes[s].edge_cost[k];
			if (nodes[t].done) continue;
			nodes[t].cost = min(nodes[t].cost, nodes[s].cost + cost);
			insert(nodes, que, t);
		}
	}
	
	for (int i=0; i<n; i++) {
		std::cout << nodes[i].id << " " << nodes[i].cost << std::endl;
	}
	
	delete[] nodes;
	
	return 0;
}

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

int n;
vector<pair<int, int>> adj[100];
int *d;

void dijkstra() {
    priority_queue<pair<int, int>> PQ;
    int d[n], color[n];

    for (int i = 0; i < n; i++) {
        d[i] = INFTY;
        color[n] = WHITE;
    }
    d[0] = 0;
    PQ.push(make_pair(0, 0));

    while (!PQ.empty()) {
        pair<int, int> f = PQ.top();
        PQ.pop();

        int u = f.second;
        color[u] = BLACK;

        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[u] + adj[u][j].second < d[v]) {
                d[v] = d[u] + adj[u][j].second;
                // printf("d[%d] = %d\n", v, d[v]);
                PQ.push(make_pair(d[v] * (-1), v));
                color[v] = GRAY;
            }
        }
    }
    
    for (int i = 0; i < n; i++) {
        printf("%d %d\n", i, d[i]);
    }
}

int main() {
    scanf("%d", &n);

    // adj = new vector<pair<int, int>>[n];

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

    dijkstra();

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define INF 1<<30
struct edge{int to,cost;};
vector<edge> G[101];
int d[101];
bool visited[101];
void dijkstra(int n){
  fill(d+1,d+101,INF);
  memset(visited,false,sizeof(visited));
  for(int i=0;i<n;++i){
    int id=-1;
    for(int j=0;j<n;++j){
      if(!visited[j]){
        if(id==-1||d[id]>d[j]) id=j;
      }
    }
    visited[id]=true;
    for(int j=0;j<G[id].size();++j){
      edge e=G[id][j];
      d[e.to]=min(d[e.to],d[id]+e.cost);
    }
  }
}
int main(){
  int n; cin>>n;
  for(int i=0;i<n;++i){
    int u,k; cin>>u>>k;
    for(int j=0;j<101;++j) G[i].clear();
    for(int j=0;j<k;++j){
      int c,v; cin>>c>>v;
      edge e; e.to=c, e.cost=v;
      G[u].push_back(e);
    }
    dijkstra(n);
  }
  for(int i=0;i<n;++i) cout<<i<<" "<<d[i]<<endl;
  return 0;
}