Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

const INF = 1 << 60

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		G[i] = make([]int, N)
		for j := 0; j < N; j++ {
			G[i][j] = sc.nextInt()
		}
	}
	d := make([]int, N)
	for i := 0; i < N; i++ {
		d[i] = INF
	}
	seen := make([]bool, N)
	d[0] = 0
	ans := 0
	for {
		cur := 0
		minCost := INF
		for i := 0; i < N; i++ {
			if !seen[i] && d[i] < minCost {
				minCost = d[i]
				cur = i
			}
		}
		if minCost == INF {
			break
		}
		seen[cur] = true
		ans += d[cur]
		for i := 0; i < N; i++ {
			cost := G[cur][i]
			if cost != -1 && cost < d[i] {
				d[i] = cost
			}
		}
	}

	fmt.Fprintln(wtr, ans)
	wtr.Flush()
}

C++: #include <iostream>
 
using namespace std;
 
 
class Graph{
private:
 
  int size;
  int **graph;
 
public:
 
  Graph(int size){
    int i;
    int j;
    this->size = size;
    this->graph = new int*[size];
    for(i = 0;i < size;i++){
      this->graph[i] = new int[size];
    }
  }
 
  ~Graph(){
    int i;
    for(i = 0;i < this->size;i++){
      delete[] this->graph[i];
    }
    delete[] this->graph;
  }
 
  int getMinimum(){
    int i;
    int j;
    int min;
    int res = 0;
    int *state;

    state = new int[this->size];


    for(i = 0;i < this->size;i++){
      state[i] = 100000000;
    }
 
    for(i = 0;i < this->size;i++){
 
      for(j = 1;j < this->size;j++){
	if(graph[i][j] > 0 && graph[i][j] < state[i]){
	  state[i] = graph[i][j];
	}
      }
    }

    for(i = 0;i < this->size;i++){
      res += state[i];
    }

    return res-1;
  }
 
  void setValue(int x,int y,int value){
    this->graph[x][y] = value;
  }
 
};
 
int main(){
 
  int i;
  int j;
  int n;
  int a;
 
  Graph *graph;
 
  cin >> n;
 
  graph = new Graph(n);
 
  for(i = 0;i < n;i++){
    for(j = 0;j < n;j++){
      cin >> a;
      graph->setValue(i,j,a);
    }
  }
 
  cout << graph->getMinimum() << endl;
 
  delete graph;
 
  return 0;

}

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++: //
// Created by tattsun on 2017/02/16.
//

#include <iostream>

#define MAX_N 101
#define INFTY 20000
#define NIL -1

enum Color {
    White,
    Glay,
    Black,
};

using namespace std;

int n;
int w[MAX_N][MAX_N];
int d[MAX_N], p[MAX_N];
Color color[MAX_N];

int min(int x, int y) {
    if(x < y) return x;
    return y;
}

int solve() {
    d[0] = 0;

    while(true) {
        int u = NIL, c = INFTY;

        for(int i=0; i<n; i++) {
            if(d[i] < c && color[i] != Black) {
                u = i;
                c = d[i];
            }
        }

        if(u == NIL)
            break;

        color[u] = Black;

        for(int i=0; i<n; i++) {
            if(color[i] != Black && w[u][i] != INFTY) {
                if(d[i] > w[u][i]) {
                    d[i] = w[u][i];
                    p[i] = u;
                    color[i] = Glay;
                }
            }
        }
    }


    int tc = 0;
    for(int i=0; i<n; i++) {
        if(color[i] == Black) {
            tc += w[i][p[i]];
        }
    }
    return tc;
}

int main() {
    for (int i = 0; i < MAX_N; i++) {
        d[i] = INFTY;
        p[i] = INFTY;
        color[i] = White;
        for (int j = 0; j < MAX_N; j++)
            w[i][j] = INFTY;
    }

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

    cout << solve() << endl;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
using namespace std;
const int num = 100;
int v[num][num], n, c[num], p[num], d[num];;
inline int mini(int k) {
	for (int i = 0; i < n; i++) {
		d[i] = 99999999;
	}

	d[k] = 0;
	p[k] = -1;
	while (1) {
		int minv = 99999999, u = -1;
		for (int i = 0; i < n; i++) {
			if (d[i] < minv && c[i] == 0) {
				minv = d[i];
				u = i;
			}
		}
		if (u == -1) break;
		for (int i = 0; i < n; i++) {
			if (v[u][i] != -1 && c[i] == 0) {
				if (d[i] > v[u][i]) {
					d[i] = v[u][i];
					p[i] = u;
				}
			}
		}
		c[u] = 1;
	}
	int sum = 0;
	for (int i = 0; i < n; i++) {
		if(p[i] != -1) sum += v[i][p[i]];
	}
	return sum;
}
int main() {
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			cin >> v[i][j];
		}
	}
	for (int i = 0; i < n; i++) {
		c[i] = 0;
	}
	cout << mini(0) << endl;
	return 0;
}