Go: package main

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

func getScanner(fp *os.File) *bufio.Scanner {
	scanner := bufio.NewScanner(fp)
	scanner.Split(bufio.ScanWords)
	scanner.Buffer(make([]byte, 500001), 500000)
	return scanner
}

func getNextString(scanner *bufio.Scanner) string {
	scanner.Scan()
	return scanner.Text()
}

func getNextInt(scanner *bufio.Scanner) int {
	i, _ := strconv.Atoi(getNextString(scanner))
	return i
}

func main() {
	fp := os.Stdin
	if len(os.Args) > 1 {
		fp, _ = os.Open(os.Args[1])
	}

	scanner := getScanner(fp)
	writer := bufio.NewWriter(os.Stdout)

	n := getNextInt(scanner)

	g := makeGraph(n)
	for i := 0; i < n; i++ {
		u := getNextInt(scanner)
		k := getNextInt(scanner)
		for ii := 0; ii < k; ii++ {
			v := getNextInt(scanner)
			c := getNextInt(scanner)
			g[u][v] = c
		}
	}

	ans := make([]int, n)
	im := make(IntMap, 1)
	im.increment(0)
	for len(im) < n {
		min := 1 << 30
		x := -1
		for u := range im {
			for v := 0; v < n; v++ {
				if im.get(v) != 0 {
					continue
				}
				if min > ans[u]+g[u][v] {
					min = ans[u] + g[u][v]
					x = v
				}
			}
		}
		im.increment(x)
		ans[x] = min
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(writer, fmt.Sprintf("%d %d", i, ans[i]))
	}
	writer.Flush()
}

func makeGraph(n int) [][]int {
	g := make([][]int, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for ii := 0; ii < n; ii++ {
			g[i][ii] = 1 << 30
		}
	}

	return g
}

// IntMap ...
type IntMap map[int]int

func (m IntMap) get(key int) int {
	if _, ok := m[key]; ok {
		return m[key]
	}
	return 0
}
func (m IntMap) increment(key int) {
	if _, ok := m[key]; ok == false {
		m[key] = 0
	}
	m[key]++
}

C++: #include<stdio.h>

#define MAX 500
static const int INFTY = (1<<21);
 
int main(){
  int n, i, j, e, sum,k,a,v1;
  int key,p[MAX],v[MAX],u,c[MAX],m[MAX][MAX];
   
  scanf("%d", &n);
  for ( i = 0; i< n; i++ ){
    for ( j = 0; j < n; j++ ){
      m[i][j] = INFTY;
    }
  }
   
  for ( i = 0; i < n; i++ ){
    scanf("%d %d", &u, &k);
    for ( j = 0; j < k; j++ ){
      scanf("%d %d", &v1, &a);
      m[u][v1] = a;
    }
  }
  for(i=0;i<n;i++){
    c[i]=INFTY;
    p[i]=-1;
    v[i]=0;
  }
  c[0]=0;
 
  while(1){
    key=INFTY;
    u=-1;
    for(i=0;i<n;i++){
      if(key>c[i] && !v[i]){
    u=i;
    key=c[i];
      }
    }
    if(u==-1)break;
    v[u]=1;
    for(j=0;j<n;j++){
      if(m[u][j]+c[u]<c[j] && !v[j]){
    p[j]=u;
    c[j]=c[u]+m[u][j];
      }
    }
  }
   
  for ( i = 0; i < n; i++ ){
    printf("%d %d\n", i, (c[i]==INFTY?-1:c[i]));
  }
   
  return 0;
}

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

// int n;
// vector<vector<int>> a(100,vector<int>(100, -1)); // 各頂点間の重みを表す隣接行列
// vector<int> d(100, -1);

// void dijkstra(int start) {
//     vector<int> s;
    
//     s.push_back(start);
//     d[start] = 0;
//     while (s.size() < n) {
//         int min_v = 10000001, min_i;
//         rep(i, s.size()) {
//             int cur = s[i];
//             rep(j, n) {
//                 int adj = a[cur][j];
//                 if (adj != -1 && d[j] == -1 && d[cur] + adj < min_v) {
//                     min_v = d[cur] + adj;
//                     min_i = j;
//                 }
//             }
//         }
//         s.push_back(min_i);
//         d[min_i] = min_v;
//     }
// }

// int main() {
//     scanf("%d", &n);
//     rep(i, n) {
//         int u, k;
//         scanf("%d %d", &u, &k);
//         rep(j, k) {
//             int v, c;
//             scanf("%d %d", &v, &c);
//             a[u][v] = c;
//         }
//     }
//     dijkstra(0);
//     rep(i, n) {
//         printf("%d %d\n", i, d[i]);
//     }
// }

#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < n; i++)

const int INF = 1000000000;
int n;
vector<vector<pair<int,int>>> e;
vector<int> d;
vector<bool> t;
void dijkstra(int start) {
    d[start] = 0;
    priority_queue<pair<int,int>, vector<pair<int,int>>, greater<pair<int,int>>> pq;
    pq.push({d[start],start});
    while (not pq.empty()) {
        int u = pq.top().second; // uは最短経路木に含まれない頂点のうちd[u]が最小であるもの
        pq.pop();
        t[u] = true; // uを最短経路木に含ませる
        rep(j, e[u].size()) {
            int v = e[u][j].first; // uの隣接点
            if (t[v] == false) { // 隣接点のうち最短経路木に含まれないもの
                if (d[u] + e[u][j].second < d[v]) { // e[u][j].secondはuから隣接点までの距離
                    d[v] = d[u] + e[u][j].second;
                    pq.push({d[v],v});
                }
            }
        }
    }
}

int main() {
    cin >> n;
    e.resize(n);
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        rep(j, k) {
            int v, c;
            cin >> v >> c;
            e[u].push_back({v,c});
        }
    }
    d.resize(n,INF);
    t.resize(n,false);
    dijkstra(0);
    rep(i, n) {
        printf("%d %d\n", i, d[i]);
    }
}

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

const int INF = 1 << 29;

int main()
{
    int n,u,k,v,c;
    int V[101][101];
    fill((int*)V, (int*)(V + 101), INF);
    
    cin >> n;
    for(int i = 0; i < n; ++i){
        V[i][i] = 0;
    }
    
    for(int i = 0; i < n; ++i){
        cin >> u >> k;
        for(int j = 0; j < k; ++j){
            cin >> v >> c;
            V[u][v] = c;
        }
    }
    
    for(int k = 0; k < n; ++k){
        for(int i = 0; i < n; ++i){
            for(int j = 0; j < n; ++j){
                V[i][j] = min(V[i][j],V[i][k] + V[k][j]);
            }
        }
    }
    
    for(int i = 0; i < n; ++i){
        cout << i << ' ' << V[0][i] << endl;
    }
    
}

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];

void dijkstra(){
    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;
        }
    }
    
    dijkstra();
}