Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const (
	INFTY = 1 << 21
	NIL   = -1
)

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph [][]int

func (g *Graph) dikstra(n int) string {
	var (
		u, minv = 0, 0
	)

	d := make([]int, n)
	color := make([]int, n)

	for i := 0; i < n; i++ {
		d[i] = INFTY
		color[i] = WHITE
	}
	d[0] = 0
	color[0] = GRAY

	for {
		minv = INFTY
		u = -1
		for 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 v := 0; v < n; v++ {
			if color[v] != BLACK && (*g)[u][v] != INFTY {
				if d[v] > d[u]+(*g)[u][v] {
					d[v] = d[u] + (*g)[u][v]
					color[v] = GRAY
				}
			}
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d ", i))
		if d[i] == INFTY {
			out.WriteString(fmt.Sprintf("%d\n", -1))
			continue
		}
		out.WriteString(fmt.Sprintf("%d\n", d[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	g := make(Graph, n)
	for i := 0; i < n; i++ {
		g[i] = make([]int, n)
		for j := 0; j < n; j++ {
			g[i][j] = INFTY
		}
	}

	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())

		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			sc.Scan()
			c, _ := strconv.Atoi(sc.Text())

			g[u][v] = c
		}
	}

	return g.dikstra(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

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];

int prim(){
  int u,minv;
  int d[MAX],p[MAX],color[MAX];

  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){
      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]>M[u][v]){
      d[v]=M[u][v];
      p[v]=u;
      color[v]=GRAY;
      }
    }
  }
  }
  int sum=0;
  for(int i=0;i<n;i++){
    if(p[i]!=-1) sum+=M[i][p[i]];
  }
  return sum;
}

int main(){
  cin >>n;

  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      int e; cin >>e;
      M[i][j] =(e==-1) ? INFTY : e;
    }
  }

  cout << prim() << endl;

  return 0;
}

C++: #include<cstdio>
#include<vector>
#include<algorithm>
#include<utility>
#include<numeric>
#include<iostream>
#include<array>
#include<string>
#include<sstream>
#include<stack>
#include<queue>
#include<list>
#include<functional>
#define _USE_MATH_DEFINES

#include<math.h>
#include<map>

#define SENTINEL 1000000001

#define min(a,b) (a)>(b)?(b):(a)
#define max(a,b) (a)>(b)?(a):(b)

using namespace std;

/*struct OwnNode
{
	vector<int> to;
	vector<int> to_cost;

	int id;
	bool checked;
	int cost;

	OwnNode(int id):id(id),checked(false),cost(-1){}

	bool operator<(const OwnNode& node)const
	{
		return cost < node.cost;
	}

	bool operator>(const OwnNode& node)const
	{
		return cost > node.cost;
	}

	OwnNode operator-(const OwnNode& node)const
	{
		return cost - node.cost;
	}
};*/

int d[100][100];

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

	for (int i = 0; i < n; i++)for (int j = 0; j < n; j++)
	{
		d[i][j] = 100000000;
	}

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

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

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

	for (int i = 0; i < n; i++)
	{
		printf("%d %d\n", i, d[0][i]);
	}

	/*vector<OwnNode> nodes;

	for (int i = 0; i < n; i++)
	{
		int id, k;
		cin >> id >> k;

		nodes.push_back(OwnNode(id));

		for (int j = 0; j < k; j++)
		{
			int v, c;
			cin >> v >> c;
			nodes[i].to.push_back(v);
			nodes[i].to_cost.push_back(c);
		}
	}

	priority_queue<OwnNode, vector<OwnNode>, greater<OwnNode>> pq;

	nodes[0].cost = 0;
	pq.push(nodes[0]);

	while (pq.size() != 0)
	{
		OwnNode tn = pq.top();
		pq.pop();

		nodes[tn.id].checked = true;

		for (int i = 0; i != tn.to.size(); i++)
		{
			if (nodes[tn.to[i]].checked)continue;
			if (nodes[tn.to[i]].cost == -1)
			{
				nodes[tn.to[i]].cost = tn.to_cost[i];
			}
			else
			{
				nodes[tn.to[i]].cost = min(nodes[tn.to[i]].cost, tn.to_cost[i] + tn.cost);
			}
			pq.push(nodes[tn.to[i]]);
		}
	}

	for (auto& node : nodes)
	{
		
		printf("%d %d\n", node.id, node.cost);
	}*/

	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#define MAX 101
#define INF 1000001
using namespace std;

int n, isSelected[MAX], dist[MAX];
vector<pair<int, int>> ver[MAX];

void initDijkstra(void);
void dijkstra(void);
bool doesFinished(void);

int main() {
	int i, j, id, k, v, c;
	cin >> n;
	for (i = 0; i < n; i++) {
		cin >> id >> k;
		for (j = 0; j < k; j++) {
			cin >> v >> c;
			ver[id].push_back(make_pair(v, c));
		}
	}

	initDijkstra();

	while (!doesFinished())dijkstra();

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

	return 0;
}

void initDijkstra(void) {

	dist[0] = 0;
	isSelected[0] = 1;
	for (int i = 1; i <= n; i++)dist[i] = INF;

	vector<pair<int, int>>::iterator itv;

	for (itv = ver[0].begin(); itv != ver[0].end(); itv++) {
		dist[itv->first] = itv->second;
	}

}

void dijkstra(void) {
	int i, minu, mindist = INF;
	vector<pair<int, int>>::iterator itv;

	for (i = 0; i < n; i++) {
		if (isSelected[i] == 0)continue;
		for (itv = ver[i].begin(); itv != ver[i].end(); itv++){
			if (isSelected[itv->first] == 1)continue;
			if (itv->second < mindist) {
				mindist = itv->second;
				minu = itv->first;
			}
		}
	}
	isSelected[minu] = 1;
	//dist[minu] = dist[minp] + mindist;
	for (itv = ver[minu].begin(); itv != ver[minu].end(); itv++) {
		if (isSelected[itv->first] == 1)continue;
		dist[itv->first] = min(dist[minu] + itv->second, dist[itv->first]);
	}
}

bool doesFinished(void) {
	for (int i = 0; i < n; i++) {
		if (isSelected[i] == 0)return false;
	}
	return true;
}