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>
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];
int prim()
{
    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;
        }
    }
    prim();
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long
int e[111][111],d[111];
int used[111];
signed main(){
  int n;
  cin>>n;
  int INF=1LL<<55LL;
  for(int i=0;i<n;i++)
    for(int j=0;j<n;j++)
      e[i][j]=INF;
  for(int i=0;i<n;i++){
    int u,k;
    cin>>u>>k;
    for(int j=0;j<k;j++){
      int v,c;
      cin>>v>>c;
      e[u][v]=min(e[u][v],c);
    }
  }
  memset(used,0,sizeof(used));
  for(int i=0;i<n;i++) d[i]=INF;
  d[0]=0;
  while(1){
    int u=-1;
    for(int i=0;i<n;i++){
      if(used[i]) continue;
      if(d[i]==INF) continue;
      if(u<0||d[i]<d[u]) u=i;
    }
    if(u<0) break;
    used[u]=1;
    for(int i=0;i<n;i++){
      d[i]=min(d[i],d[u]+e[u][i]);
    }
  }
  for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
  return 0;
}

C++: #include<cstdio>
#include<iostream>
using namespace std;
int adj[101][101], d[101], visited[101];
int n, INFTY = (1<<30);
void dijkstra()
{
  for(int i=0; i<n; i++)
  {
    visited[i] = 0; d[i] = INFTY;
  }
  d[0] = 0;

  while(1)
  {
    int minc = INFTY, u=-1;
    for(int i=0; i<n; i++)
    {
      if(d[i] < minc && visited[i] == 0)
      {
        minc = d[i];
        u = i;
      }
    }
    if(minc == INFTY) break;
    visited[u] = 1;
    for(int i=0; i<n; i++)
    {
      if(adj[u][i] != -1 && visited[i]==0)
      {
        if(d[i] > d[u] + adj[u][i])
          d[i] = d[u] + adj[u][i];
      }
    }
  }
  for(int i=0; i<n; i++)
    printf("%d %d\n", i, d[i]);
}
int main()
{
  scanf("%d", &n);
  int u, k, c, v;
  for(int i=0; i<n; i++)
    for(int j=0; j<n; j++)
      adj[i][j] = -1;
  for(int i=0; i<n; i++)
  {
    scanf("%d%d", &u, &k);
    for(int j=0; j<k; j++)
    {
      scanf("%d%d", &v, &c);
      adj[u][v] = c;
    }
  }
  dijkstra();

  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;

void dijkstra(int n, int m[MAX][MAX]) {
    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 (true) {
        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() {
    int n, m[MAX][MAX];
    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(n, m);
}