Go: package main

import (
	"strconv"
	"fmt"
	"bufio"
	"os"
)
const INF = 1 << 21
var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}


func main() {
	scanner.Split(bufio.ScanWords)
	n := nextInt()
	adj := make([][]int, n)
	for i := range adj {
		adj[i] = make([]int, n)
	}

	for i := 0;i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			v := nextInt()
			c := nextInt()
			adj[u][v] = c
		}
	}

	// for i := range adj {
	// 	fmt.Println(adj[i])
	// }

	dist := make([]int, n)
	prev := make([]int, n)
	visited := make([]bool, n)
	dijkstra := func(start int, size int) {
		for i := 0; i < size; i++ {
			dist[i] = INF
			prev[i] = -1
			visited[i] = false
		}
		dist[start] = 0
		for {
			u := -1
			tmp_min := INF
			for i := 0; i < size; i++ {
				if visited[i] == false && dist[i] < tmp_min {
					tmp_min = dist[i]
					u = i
				}
			}
			if u == -1 {
				break
			}
			visited[u] = true
			for i := 0; i < size; i++ {
				if adj[u][i] > 0 {
					w := adj[u][i]
					newlen := dist[u] + w
					if newlen < dist[i] {
						dist[i] = newlen
						prev[i] = u
					}
				}
			}
		}
	}
	dijkstra(0, n)
	for i, cost := range dist {
		fmt.Printf("%d %d\n", i, cost)
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <vector>
#include <queue>
#include <cmath>
using namespace std;
const int maxn=100+10;
const int maxv=10000+10;
const int INF=1<<21;
int n;
int E;
typedef struct
{
    int from,to,cost;
}Edge;

Edge e[maxv];
int d[maxn];
void bellman_ford(int s)
{
    fill(d,d+n,INF);
    d[s]=0;
    while(true)
    {
        bool bUpdate=false;
        for(int i=0;i<E;i++)
        {
            Edge es=e[i];
            if(d[es.from]!=INF&&d[es.to]>d[es.from]+es.cost)
            {
                d[es.to]=d[es.from]+es.cost;
                bUpdate=true;

            }
        }
        if(!bUpdate) break;

    }
    for(int i=0;i<n;i++)
    printf("%d %d\n",i,d[i]);
}
int main()
{
//    freopen("in.txt","r",stdin);
    scanf("%d",&n);
    int id,c;
    E=0;
    for(int i=0; i<n; i++)
    {
        scanf("%d%d",&id,&c);
        while(c--)
        {
            scanf("%d%d",&e[E].to,&e[E].cost);
            e[E].from=id;
            E++;
        }
    }
    bellman_ford(0);

    return 0;
}

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

int min(int i,int j){
 return i>j?j:i;
}

int main(void){
 int n,u,k,c,v;
 vector<int> d;
 vector< vector<int> > edge;
 cin>>n;
 edge.resize(n);
 for(int i=0;i<n;i++){
 edge[i].resize(n);
}
 d.resize(n);
 d[0]=0;
 for(int i=1;i<n;i++){
  d[i]=100000000;
}
 for(int i=0;i<n;i++){
  for(int j=0;j<n;j++){
   edge[i][j]=1000000000;
  }
}
for(int i=0;i<n;i++){
 edge[i][i]=0;
}
for(int i=0;i<n;i++){
 cin>>u>>k;
 for(int j=0;j<k;j++){
  cin>>v>>c;
  edge[u][v]=c;
 }
}
for(int i=0;i<n;i++){
 for(int j=0;j<n;j++){
  for(int k=0;k<i;k++){
  d[j]=min(d[j],d[k]+edge[k][j]);}
 }
}

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

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18;
const int inf = 1e9;
#define rep(i, n) for (int i = 0; i < n; i++)
using Graph = vector<vector<int>>;
using pint = pair<int, int>;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
int dxx[8] = {1, 1, 1, 0, 0, -1, -1, -1}, dyy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};

const int MAX = 100;
int cost[MAX][MAX];
int n;

void dijkstra() {
    int d[n];
    bool seen[n] = {};
    rep (i, n) { d[i] = inf; }
    d[0] = 0;
    while (1) {
        int minc = inf, now;
        rep (i, n) {
            if (minc > d[i] && !seen[i]) {
                minc = d[i];
                now = i;
            }
        }
        seen[now] = 1;
        if (minc == inf) break;
        rep (i, n) {
            if (cost[now][i] != inf && !seen[i]) {
                if (d[i] > cost[now][i] + d[now]) {
                    d[i] = cost[now][i] + d[now];
                }
            }
        }
    }
    rep (i, n) { cout << i << " " << d[i] << "\n"; }
    return;
}

int main() {
    cin >> n;
    rep (i, n) rep (j, n) cost[i][j] = inf;
    rep (i, n) {
        int now, k, next, c;
        cin >> now >> k;
        rep (i, k) {
            cin >> next >> c;
            cost[now][next] = c;
        }
    }
    dijkstra();
}