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++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <list>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <queue>
#include <iomanip>
#define INF 214748364
 
using namespace std;

#define MAX_V 101

int d[MAX_V][MAX_V];  // d[u][v]は辺e=(u,v)のコスト(存在しない場合はINF、ただしd[i][i]=0とする)
int V;                // 頂点数
void warshall_floyd(int n) {
	V = n;

	for (int k = 0; k < V; k++)
		for (int i = 0; i < V; i++)
			for (int j = 0; j < V; j++) 
				d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
}

int main(void)
{
	int n, u, v, k, c;

	cin >> n;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			if (i == j) d[i][j] = 0; 
			else d[i][j] = INF;

		}
	}

	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v >> c;
			d[u][v] = c;
		}
	}
	
	warshall_floyd(n);

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


	return (0);
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
typedef float fl;
typedef long long ll;

static const int MAX = 100;
static const int INF = (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];

    rep(i,n) {
        d[i] = INF;
        color[i] = WHITE;
    }

    d[0] = 0;
    color[0] = GRAY;
    // 最短経路の候補の中で最小の頂点を選ぶ
    while(1){
        minv = INF;
        int u = -1;
        rep(i,n) {
            if (minv > d[i] && color[i] != BLACK) {
                u = i;
                minv = d[i];
            }
        }
        if (u == -1) break;
        color[u] = BLACK;

    // 次の最短経路の頂点を見つける
        rep(v,n) {
            if (color[v] != BLACK && M[u][v] != INF){
                if (d[v] > d[u] + M[u][v]) {
                    d[v] = d[u] + M[u][v];
                    color[v] = GRAY;
                }
            }
        }
    }
    rep(i,n){
        cout << i << " " << ((d[i] == INF)? -1 : d[i]) << endl;
    }
}

int main(){
    cin >> n;
    rep(i,n){
        rep(j,n) M[i][j] = INF;
    }

    int k, c, u, v;
    rep(i,n){
        cin >> u >> k;
        rep(j,k){
            cin >> v >> c;
            M[u][v] = c;
        }
    }
    dijkstra();
    return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> Pair;
ll inf = 1e10;
int MAX_V;

ll V, E;
vector<Pair> G[100010];
ll d[100010];

void dijkstra(ll s) {
    priority_queue<Pair, vector<Pair>, greater<Pair>> que;
    fill(d, d + V, inf);
    d[s] = 0;
    que.push(Pair(0, s));
    
    while (!que.empty()) {
        Pair p = que.top();
        que.pop();
        
        ll v = p.second;
        if (d[v] < p.first) continue;
        for (int i = 0; i < G[v].size(); i++) {
            Pair e = G[v][i];
            if (d[e.first] > d[v] + e.second) {
                d[e.first] = d[v] + e.second;
                que.push(Pair(d[e.first], e.first));
            }
        }
    }
}

int main() {
    cin >> V;
    for (int i = 0; i < V; i++) {
        int a, et;
        cin >> a >> et;
        for (int j = 0; j < et; j++) {
            int b;
            ll r;
            cin >> b >> r;
            G[a].emplace_back(b, r);
            //G[b].emplace_back(a, r);
        }
    }

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

}

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

#define MAX   100
#define INFTY (1 << 21)
#define WHITE 0
#define GRAY  1
#define BLACK 2

int n, M[MAX][MAX];

void dijkstra() {
  int d[MAX], p[MAX], color[MAX];
  int minv, u;
  for ( int i = 0; i < n; i++ ) {
    d[i] = INFTY;
    p[i] = -1;
    color[i] = WHITE;
  }

  d[0] = 0;
  while ( 1 ) {
    minv = INFTY;
    u = -1;
    for ( int i = 0; i < n; i++ ) {
      if ( minv > d[i] && color[i] != BLACK ) {
        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;
}