Go: package main

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

func main() {
	r := bufio.NewReader(os.Stdin)

	var n int
	fmt.Fscan(r, &n)
	cs := make([]map[int]int, n) // []v_i -> c_i
	for h := 0; h < n; h++ {
		var u, k int
		fmt.Fscan(r, &u, &k)
		m := make(map[int]int)
		for i := 0; i < k; i++ {
			var v, c int
			fmt.Fscan(r, &v, &c)
			m[v] = c
		}

		cs[u] = m
	}

	q := make(map[int]int)
	q[0] = 0
	visited := make(map[int]struct{})
	out := make([]int, n)

	for len(q) > 0 {
		u := top(q)
		for uu, c := range cs[u] {
			// Consider the connection between u and uu.
			if _, ok := visited[uu]; ok {
				continue
			}
			if d, ok := q[uu]; !ok || d > q[u]+c {
				q[uu] = q[u] + c
			}
		}

		out[u] = q[u]
		delete(q, u)
		visited[u] = struct{}{}
	}

	for u, d := range out {
		fmt.Println(u, d)
	}
}

func top(q map[int]int) int {
	minu := -1
	min := -1
	for u, d := range q {
		if min < 0 || d < min {
			minu = u
			min = d
		}
	}

	return minu
}

C++: #include <iostream>
#include <fstream>
#include <stdio.h>
#include <algorithm>

using namespace std;

static const int MAX = 100;
static const int INFTY = (1 << 21);
static const int WHITE = 0;
static const int BLACK = 1;

int n;
int M[MAX][MAX];

void prim(){
    int minv;
    int d[MAX], color[MAX];
    
    for(int i=0; i<n; i++){
        d[i] = INFTY;
        color[i] = WHITE;
    }
    
    d[0] = 0;
    
    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 i=0; i<n; i++){
            if(M[u][i] != INFTY && color[i] != BLACK){
                if(d[i] > d[u]+M[u][i]){
                    d[i] = d[u]+M[u][i];
                }
            }
        }
    }
    
    for(int i=0; i<n; i++){
        cout << i << " " << (d[i] == INFTY ? -1 : d[i]) << endl;
    }
}

int main(int argc, const char * argv[]) {
    // input from txt
    
    /////////
    //write//
    /////////
    
    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 <stdio.h>
#include <iostream>
using namespace std;

#define NIL -1
#define INF 100000000
#define WHITE 1
#define GREY 2
#define BLACK 3
#define N_MAX 100

int G[N_MAX][N_MAX];
int V[N_MAX];
int V_value[N_MAX];

void init(){
    for(int i = 0; i < N_MAX; i++){
        V[i] = WHITE;
        V_value[i] = INF;
    }

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

int main(void){
    init();
    int n;
    scanf("%d\n", &n);

    for(int i = 0; i < n; i++){
        int u, k;
        scanf("%d %d", &u, &k);
        for(int j = 0; j < k; j++){
            int v, c;
            scanf("%d %d", &v, &c);
            G[u][v] = c;
        }
    }

    V[0] = BLACK;
    V_value[0] = 0;
    int new_node = 0;
    
    while(1){
        for(int i = 0; i < n; i++){
            if(G[new_node][i] != NIL && V[i] == WHITE){
                V_value[i] = min(V_value[i], V_value[new_node] + G[new_node][i]);
            }
        }

        int min_index = NIL;
        int min_value = INF;
        for(int i = 0; i < n; i++){
            if(V[i] == WHITE && V_value[i] < min_value){
                min_value = V_value[i];
                min_index = i;
            }
        }
        if(min_index == NIL){
            break;
        }else{
            new_node = min_index;
            V[new_node] = BLACK;
            V_value[new_node] = min_value;
        }
    }
    
    for(int i = 0; i < n; i++){
        printf("%d %d\n", i, V_value[i]);
    }

    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <stack>
#include <vector>
using namespace std;
const int maxx=110;
const int infinity=(1<<21);

int A[maxx][maxx],d[maxx];
bool flag[maxx];

int main (){
	int n,a,b,c;
	cin>>n;
	for(int i=0;i<maxx;i++){
		flag[i]=false;
		d[i]=infinity;
		for(int j=0;j<maxx;j++){
			A[i][j]=infinity;
		}
	}
	for(int i=0;i<n;i++){
		cin>>a>>b;
		for(int j=0;j<b;j++){
			cin>>c>>A[a][c];
		}
	}
	
	d[0]=0;
	while(1){
		int minv=infinity,mini=-1;
		for(int i=0;i<n;i++){
			if(flag[i]==false && d[i]<minv){
				minv=d[i];
				mini=i;
			}
		}
		if(mini==-1 || minv==infinity) break;
		flag[mini]=true;
		for(int i =0;i<n;i++){
			if(A[mini][i]!=infinity && flag[i]==false){
				if(d[mini]+A[mini][i]<d[i]){
					d[i]=d[mini]+A[mini][i];
				}
			}
		}
		
	}
	cout<<n<<endl;
	for(int i=0;i<n;i++) cout<<i<<" "<<d[i]<<endl;
	
	return 0;

}