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<bits/stdc++.h>

using namespace std;

struct edge
{
    int from,to,cost;
    edge(int _from=0,int _to=0,int _cost=0)
    {
        from=_from;to=_to;cost=_cost;
    }
}edg[10010];

int n,m;

int d[110];
const int INF=1e9+7;
bool bellman(int s)
{
    fill(d,d+n,INF);
    d[s]=0;

    for(int i=0;i<n;i++)
    {
        for(int j=0;j<m;j++)
        {
            edge e=edg[j];
            if(d[e.to]>d[e.from]+e.cost)
            {
                d[e.to]=d[e.from]+e.cost;
                if(i==n-1) return false;
            }
        }
    }
    return true;
}

int main()
{

    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    while(cin>>n)
    {
        m=0;
        int a,b,c,dd;
        for(int i=0;i<n;i++)
        {
            cin>>a>>b;
            for(int j=0;j<b;j++)
            {
                cin>>c>>dd;
                edg[m++]=edge(a,c,dd);
            }
        }
        bellman(0);

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



    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <queue>
#include <vector>
#include <cmath>
#include <cctype>
#define rep(i,a,b) for(int i=(a);i<b;i++)
#define INF 1000000000
#define MAX_N 100000000
#define MAX 
using namespace std;
bool debug=false;

int cost[105][105];
int d[105];
bool used[105];
int n;

void Input(){
  cin>>n;
  rep(i,0,n)rep(j,0,n)cost[i][j]=INF;
  for(int i=0;i<n;i++){
  	int from,to,num,c;
  	cin>>from>>num;
  	for(int j=0;j<num;j++){
  		cin>>to>>c;
  		cost[from][to]=c;
  	}
  }
  rep(i,0,105){
    used[i]=false;
    d[i]=INF;
  }
}

void solve(){
  d[0]=0;
  while(1){
    int vertex=-1;

    for(int i=0;i<n;i++){
      if(!used[i]&&(vertex==-1||d[i]<d[vertex])){
	    vertex=i;
      }
    }
    if(vertex==-1)break;
    used[vertex]=true;
    for(int i=0;i<n;i++){
      d[i]=min(d[i],d[vertex]+cost[vertex][i]);
    }
  }
}

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

C++: #include <iostream>
#include <iomanip>


using namespace std;

const int  MAXN = 150;
const int IFNTY = 1 << 20;
const int NIL = -1;


void dijkstra(int adj_matrix[][MAXN], int n, int u, int dis[]);


int main()
{
	int adj_matrix[MAXN][MAXN];
	
	
	
	for (int i = 0; i < MAXN; i++)
	{
		for (int j = 0; j < MAXN; j++)
		{
			adj_matrix[i][j] = IFNTY;			
		}
	}

	int n;
	cin >> n;
	
	for (int i = 1; i <= n; i++)
	{
		int ID1, degree;
		cin >> ID1 >> degree;
		for (int j = 1; j <= degree; j++)
		{
			int ID2, weight;	
			cin >> ID2 >> weight;
			adj_matrix[ID1][ID2] = weight;		
		}
	}	
	
//	for (int i = 0; i < n; i++)
//	{
//		for (int j = 0; j < n; j++)
//		{
//			if (adj_matrix[i][j] == IFNTY)
//				cout << setw(3) << "-" << " ";
//			else
//				cout << setw(3) << adj_matrix[i][j] << " ";			
//		}
//		cout << endl;
//	}

	int dis[MAXN];	
	
	dijkstra(adj_matrix, n, 0, dis);
	
	for (int i = 0; i < n; i++)
	{
		cout << i << ' ' << dis[i] << endl;
	}
}



void dijkstra(int adj_matrix[][MAXN], int n, int u, int dis[])
{
	bool visited[MAXN] = {0};
	
	for (int v = 0; v < n; v++)
	{
		dis[v] = adj_matrix[u][v];
	}
	
	dis[u] = 0;
	visited[u] = true;
	
	while (true)
	{
		int w = NIL;
		int min = IFNTY;
		for (int v = 0; v < n; v++)
		{
			if (min > dis[v] && !visited[v])
			{
				w = v;
				min = dis[v];
			}
		}
		
		
		if (w == NIL) break;
		
		visited[w] = true;
		for (int v = 0; v < n; v++)
		{
			if (dis[v] > dis[w] + adj_matrix[w][v])
			{
				dis[v] = dis[w] + adj_matrix[w][v];
			}
		}
	}
}

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();

  return 0;
}

C++: #include <iostream>
#include <limits>

constexpr int MAXN = 100;
int G[MAXN][MAXN];
int P[MAXN];
int D[MAXN];
int C[MAXN];

constexpr int MAXINT = std::numeric_limits<int>::max();

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

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

    for (int i = 0; i < n; i++) {
        D[i] = MAXINT;
    }

    for (int i = 0; i < n; i++) {
        int id, e_num;
        std::cin >> id >> e_num;
        for (int j = 0; j < e_num; j++) {
            int t;
            std::cin >> t;
            std::cin >> G[id][t];
        }
    }

    int r = 0;
    D[r] = 0;
    while (true) {
        int mincost = MAXINT;
        int m;
        for (int i = 0; i < n; i++) {
            if ((C[i] == 0) && (D[i] < mincost)) {
                mincost = D[i];
                m = i;
            }
        }

        if (mincost == MAXINT) {
            break;
        }

        C[m] = 1;
        for (int i = 0; i < n; i++) {
            if ((C[i] != 1) && (G[m][i] != MAXINT)&& ((D[m] + G[m][i]) < D[i])) {
                P[i] = m;
                D[i] = D[m] + G[m][i];
            }
        }
    }

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

}