Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
type Node struct {
	cost int
	done bool
}

type Edge struct {
	to, cost int
}

const INF = 1 << 60

func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	nodes := make([]Node, N)
	for i := 0; i < N; i++ {
		nodes[i].cost = INF
	}
	E := make([][]Edge, N)
	for i := 0; i < N; i++ {
		id, k := sc.nextInt(), sc.nextInt()
		for j := 0; j < k; j++ {
			to, cost := sc.nextInt(), sc.nextInt()
			E[id] = append(E[id], Edge{to, cost})
		}
	}
	nodes[0].cost = 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			n := nodes[i]
			if !n.done && n.cost < minCost {
				cur = i
				minCost = n.cost
			}
		}
		if minCost == INF {
			break
		}
		nodes[cur].done = true
		for i := 0; i < len(E[cur]); i++ {
			to, cost := E[cur][i].to, E[cur][i].cost+nodes[cur].cost
			if !nodes[to].done && cost < nodes[to].cost {
				nodes[to].cost = cost
			}
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprintln(wtr, i, nodes[i].cost)
	}
	wtr.Flush()
}

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;
}

C++: #include<iostream>
using namespace std;
#define MAX 100+5
#define white 0
#define black 1
#define INF 100000*100+5
int m[MAX][MAX],color[MAX],d[MAX],num;
void dijkstra(){
	d[0]=0;int now_node;
while(true){
	int minc=INF;
	for(int i=0;i<num;i++){
		if(!color[i]&&d[i]<minc){
			minc=d[i];now_node=i;
		}
	}
     	if(minc==INF) break;
		color[now_node]=black;
		for(int i=0;i<num;i++){
			if(color[i]==white&&m[now_node][i]+d[now_node]<d[i]){
				d[i]=d[now_node]+m[now_node][i];
			}
		}
	
}
return ;
}
int main(){
	cin>>num;
	for(int i=0;i<num;i++){
		for(int j=0;j<num;j++){
			m[i][j]=INF;
		}
	}
	int row,n,col,val;
	for(int i=0;i<num;i++){
		cin>>row;
		cin>>n;
		for(int j=0;j<n;j++){
			cin>>col>>val;
			m[row][col]=val;
		}
	}
	for(int i=0;i<num;i++){
		d[i]=INF;color[i]=0;
	}
	dijkstra();
	for(int i=0;i<num;i++){
		cout<<i<<" "<<d[i]<<endl;
	}
}