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 <bits/stdc++.h>

#define REP(i, n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()
const int INF = 1e9;

using namespace std;
int n;
int res = 0;
struct node {
    int id;
    int dist;
    bool searched;
};

node v[100];
int edge[100][100];

int main() {
    cin >> n;
    REP(i, n) {
        int u, k;
        cin >> u >> k;
        v[u].id = u;
        v[u].dist = INF;
        v[u].searched = false;
        REP(j, n) edge[i][j] = INF;
        REP(j, k){
            int to, cost;
            cin >> to >> cost;
            edge[i][to] = cost;
        }
    }
    v[0].dist = 0;
    int next = 0;
    int prev = 0;
    REP(i, n){
        int minimum = INF;
        REP(j, n){
            if(!v[j].searched && edge[prev][j] != INF){
                v[j].dist = min(v[j].dist, v[prev].dist + edge[prev][j]);
                if(minimum >= v[j].dist){
                    next = j;
                    minimum = v[j].dist;
                }
            }
        }
        v[prev].searched = true;
        prev = next;
    }
    REP(i, n) cout << i << " " << v[i].dist << endl;
    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<climits>
using namespace std;

#define N 120
int n;

int g[N][N];

int weight[N];
bool us[N];

int prim(){

  int v;
  int ans=0;
  weight[0]=0;
  
  while(true){
    v=-1;
   
    for(int i=0;i<n;i++){
      if(us[i]!=true && (v==-1 ||weight[i]<weight[v]))v=i;
    }

    if(v==-1)break;
    us[v]=true;
    ans+=weight[v];

    for(int i=0;i<n;i++){
      if(weight[i]>(g[v][i]+weight[v])){

        weight[i]=(g[v][i]+weight[v]);
        //      cout <<"fsafa"<<endl;
      }
    }
  }
  return ans;
}


int main(){

  int u,k1,c,v;

  for(int i=0;i<N;i++){
    for(int j=0;j<N;j++){
      g[i][j]=53535;
    }
  }

//load n
  cin >>n;

  //load data
  for(int i=0;i<n;i++){
    weight[i]=INT_MAX;
    us[i]=false;
    scanf("%d %d",&u,&k1);
    for(int j=0;j<k1;j++){
      scanf("%d %d",&v,&c);
      g[u][v]=c;
      //    cout <<g[i][j]<<" ";
    }
    //    cout <<endl;
  }




  //print
  prim();

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

}

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 101
#define INF 100100

static const int WHITE = 0; //not visited
static const int GRAY = 1; //visited
static const int BLACK = 2;

int n, M[MAX][MAX];
int color[MAX];
int dist_from_start[MAX];
int parent_node[MAX];

void dijkstra(int start) {
  //initialize
  for (int i = 1; i <= n; i++) {
    color[i] = WHITE;
    dist_from_start[i] = INF;
    parent_node[i] = -1;
  }

  dist_from_start[start] = 0;
  color[start] = GRAY;

  while (true) {
    int mincost = INF;
    int now = -1;

    //初回はmincost = 0になる(始点)
    for (int i = 1; i <= n; i++) {
      if (color[i] != BLACK && dist_from_start[i] < mincost) {
        mincost = dist_from_start[i];
        now = i;
      }
    }

    if (now == -1) break;

    color[now] = BLACK;

    for (int v = 1; v <= n; v++) {
      if (color[v] != BLACK && M[now][v] != INF) {
        if (dist_from_start[now] + M[now][v] < dist_from_start[v]) {
          dist_from_start[v] = dist_from_start[now] + M[now][v];
          parent_node[v] = now;
          color[v] = GRAY;
        }
      }
    }
  }

  for (int i = 1; i <= n; i++) cout << i-1 << " " << (dist_from_start[i] == INF ? -1 : dist_from_start[i]) << endl;
}

int main() {
  cin >> n;

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

  int u, k;
  for (int i = 1; i <= n; i++) {
    cin >> u >> k;
    for (int j = 1; j <= k; j++) {
      int v, t;
      cin >> v >> t;
      M[u+1][v+1] = t;
    }
  }

  dijkstra(1);

  return 0;
}

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

vector<vector<pair<int, int>>> v;
vector<int> d, color;

const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

void dijkstra(){
  priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
  q.push(make_pair(0, 0));
  d[0] = 0;

  while(!q.empty()){
    auto next = q.top(); q.pop();
    if(color[next.second] == BLACK) continue;

    color[next.second] = BLACK;

    for(auto ve : v[next.second]){
      if(color[ve.first] != BLACK && d[ve.first] > d[next.second] + ve.second){
        d[ve.first] = d[next.second] + ve.second;
        color[ve.first] = GRAY;
        q.push(make_pair(d[ve.first], ve.first));
      }
    }
  }
}

int main(){
  int n; cin >> n;

  v.resize(n);
  d.resize(n);
  color.resize(n);

  for(int i=0; i<n; ++i){
    d[i] = numeric_limits<int>::max();

    int u, k, ve, c; cin >> u >> k;
    for(int l=0; l<k; ++l){
      cin >> ve >> c;
      v[u].push_back(make_pair(ve, c));
    }
  }

  dijkstra();

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