Go: package main

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

const (
	WHITE int = iota
	GRAY
	BLACK
)

type graph struct {
	G [][]int
	C []int
	D []int
	P []int
}

var INFTY = 1 << 32

func constructGraph() *graph {
	sc := bufio.NewScanner(os.Stdin)
	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	g := make([][]int, n)
	c := make([]int, n)
	d := make([]int, n)
	p := make([]int, n)

	for i := 0; i < n; i++ {
		sc.Scan()
		fields := strings.Fields(sc.Text())
		g[i] = toIntSlice(fields)
	}

	return &graph{g, c, d, p}
}

func (g *graph) initMst() {
	for i := 0; i < len(g.G); i++ {
		g.C[i] = WHITE
		g.D[i] = INFTY
	}
	g.D[0] = 0
	g.P[0] = -1
}

func (g *graph) primMst() int {
	g.initMst()

	var u int
	for {
		mincost := INFTY
		for i := 0; i < len(g.G); i++ {
			if g.C[i] != BLACK && g.D[i] < mincost {
				mincost = g.D[i]
				u = i
			}
		}

		if mincost == INFTY {
			break
		}

		g.C[u] = BLACK

		for i := 0; i < len(g.G); i++ {
			if g.C[i] != BLACK && g.existEdge(u, i) {
				if g.G[u][i] < g.D[i] {
					g.D[i] = g.G[u][i]
					g.P[i] = u
				}
			}
		}
	}

	totalCost := 0
	for _, cost := range g.D {
		totalCost += cost
	}
	return totalCost
}

func (g *graph) existEdge(u, v int) bool {
	return g.G[u][v] != INFTY && g.G[v][u] != INFTY
}

func toIntSlice(s []string) []int {
	a := make([]int, len(s))
	for i, v := range s {
		num, _ := strconv.Atoi(v)
		if num == -1 {
			num = INFTY
		}
		a[i] = num
	}
	return a
}

func main() {
	g := constructGraph()
	fmt.Println(g.primMst())
}

C++: #include <stdio.h>
#include <stdint.h>
#include <iostream>
#include <fstream>
#include <cassert>
#include <climits>

#include <vector>
#include <string>
using namespace std;

#define DEBUG (0)

#if DEBUG
#define DPRINTF(...) do { \
    printf("D(L%d) %s: ", __LINE__, __func__); \
    printf(__VA_ARGS__); \
  } while (false)
#else
#define DPRINTF(...)
#endif // DEBUG

/*
   recursive + dfs
*/

const uint8_t kMaxN = 100;
int16_t gWeightOfVij[kMaxN][kMaxN];
int gNumOfVertices;


void printAllWeights()
{
  DPRINTF("Number of vertices %d\n", gNumOfVertices);

  for (int i = 0; i < gNumOfVertices; i++)
  {
    for (int j = 0; j < gNumOfVertices; j++)
    {
      if (j == 0)  DPRINTF("");
      printf(" %d", gWeightOfVij[i][j]);
    }
    cout << endl;
  }
}


void printAllPath()
{
  DPRINTF("Number of vertices %d\n", gNumOfVertices);

  for (int i = 0; i < gNumOfVertices; i++)
  {
    for (int j = 0; j < gNumOfVertices; j++)
    {
      if (gWeightOfVij[i][j] > 0)
        printf("%d -> %d (%d)\n", i, j, gWeightOfVij[i][j]);
    }
  }
}


vector<int16_t> getConnectedVs(int16_t v, const bool visited[])
{
  vector<int16_t> vertices;

  for (int i = 0; i < gNumOfVertices; i++)
  {
    if (gWeightOfVij[v][i] > 0 && !visited[i])
      vertices.push_back(i);
  }

#if 0
  if (vertices.size() > 0)
  {
    for (int i = 0; i < vertices.size(); i++)
    {
      if (i == 0)
        DPRINTF("v from %d to :", v);

      printf(" %d", vertices[i]);
    }

    cout << endl;
  }
#endif

  return vertices;
}


int minSpanningTreeRecursive(int16_t currentV, const bool visited[], string inpPath, string &minPath)
{
  assert(0 <= currentV && currentV < gNumOfVertices);

  bool updatedVisited[gNumOfVertices];

  for (int i = 0; i < gNumOfVertices; i++)
    updatedVisited[i] = visited[i];

  updatedVisited[currentV] = true;

  // This function ensures all of elements are unvisited
  vector<int16_t> nextVs = getConnectedVs(currentV, updatedVisited);

  if (nextVs.size() == 0)
  {
    minPath = to_string(currentV);
    return 0;
  }

  int minV = -1;
  int minScore = INT_MAX;
  string currentPath = to_string(currentV);


  if (inpPath.size())
    currentPath = inpPath + " > " + currentPath;

  for (int i = 0; i < nextVs.size(); i++)
  {
    string searchedPath = "";
    const int16_t nextV = nextVs[i];
    const int score = gWeightOfVij[currentV][nextV] + minSpanningTreeRecursive(nextV, updatedVisited, currentPath, searchedPath);

    if (minScore > score)
    {
      minV = nextV;
      minScore = score;
      minPath = searchedPath;
    }

  }

  {
    if (minPath.size())
      minPath = " > " + minPath;

    minPath = to_string(currentV) + minPath;

    DPRINTF("score %d\n", minScore);
    DPRINTF("  %s | %s\n", currentPath.c_str(), minPath.c_str());
  }

  return minScore;
}


int minSpanningTree()
{
  int16_t startV = 0;
  bool visited[gNumOfVertices];

  for (int i = 0; i < gNumOfVertices; i++)
    visited[i] = false;

  string inpPath = "", minPath;

  return minSpanningTreeRecursive(startV, visited, inpPath, minPath);
}


int main()
{
  cin >> gNumOfVertices; cin.ignore();

  DPRINTF("Number of vertices %d\n", gNumOfVertices);

  for (int i = 0; i < gNumOfVertices; i++)
  {
    for (int j = 0; j < gNumOfVertices; j++)
      cin >> gWeightOfVij[i][j];

    cin.ignore();
  }

#if DEBUG
  DPRINTF("Number of vertices %d\n", gNumOfVertices);
  //printAllWeights();
  printAllPath();
#endif // DEBUG

  cout << minSpanningTree() << endl;

  return 0;
}

C++: #define _USE_MATH_DEFINES
#include<iostream>
#include<algorithm>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<deque>
#include<queue>
#include<map>
#include<set>
#define ll long long
#define str string
#define ld long double
#define vec vector
#define vll vec<ll>
#define rep(i,a,b) for(ll i=a;i<b;i++)
#define rrep(i,b,a) for(ll i=b;i>=a;i--)
#define ALL(a) a.begin(),a.end()
#define rALL(a) a.rbegin(),a.rend()
#define kai "\n"
#define yuque priority_queue
#define ryuque(t) priority_queue<t,vec<t>,greater<t>>
#define pub push_back
#define pob pop_back
#define puf push_front
#define pof pop_front
#define mie min_element
#define mae max_element
#define tos to_string
#define sep setprecision
#define MOD 1000000007ll
using namespace std;
void solve();
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed;
	solve();
}

//nCk(mod p)
const ll NUM = 2;
ll fac[NUM], finv[NUM], inv[NUM];
void cmodf(ll p = MOD) {
	fac[0] = fac[1] = 1;
	finv[0] = finv[1] = 1;
	inv[1] = 1;
	rep(i, 2, NUM) {
		fac[i] = fac[i - 1] * i%p;
		inv[i] = p - inv[p%i] * (p / i) % p;
		finv[i] = finv[i - 1] * inv[i] % p;
	}
}
ll cmod(ll n, ll k, ll p = MOD) {
	return fac[n] * (finv[k] * finv[n - k] % p) % p;
}

//最大公約数
ll gcd(ll n, ll m) {
	ll k = n % m;
	while (k != 0) { n = m; m = k; k = n % m; }
	return m;
}
ll gcd(vector<ll> a) {
	rep(i, 1, a.size()) {
		ll k = a[i - 1] % a[i];
		while (k != 0) {
			a[i - 1] = a[i];
			a[i] = k;
			k = a[i - 1] % a[i];
		}
	}
	return a.back();
}

//最小公倍数
ll lcm(ll n, ll m) {
	ll t = n * m, k = n % m;
	while (k != 0) { n = m; m = k; k = n % m; }
	return t / m;
}
ll lcm(vector<ll> a) {
	ll n;
	rep(i, 1, a.size()) {
		n = a[i - 1] * a[i];
		ll k = a[i - 1] % a[i];
		while (k != 0) {
			a[i - 1] = a[i];
			a[i] = k;
			k = a[i - 1] % a[i];
		}
		n /= a[i];
		a[i] = n;
	}
	return n;
}

//keyの小さい方から探していった時に初めてvalueがjoken以上になる時のkey（keyが増えたらvalueも増えるか同じになるとき）
ll value(ll key) {
	/*変更*/
	return 0;
}
ll mink(ll lkey, ll rkey/*ここも調べる*/, ll joken) {
	ll mkey;
	while (lkey != rkey) {
		mkey = (lkey + rkey) / 2;
		if (value(mkey) >= joken)rkey = mkey;
		else lkey = mkey + 1;
	}
	return rkey;
}

//ペア配列の整理
struct pea {
	ll f, s;
	bool operator<(const pea &c)const {
		return f != c.f ? f < c.f : s < c.s;
	};
};

//変数定義

//再帰関数

//アルゴリズム
void solve() {
	ll n; cin >> n;
	vec<vll> c(n, vll(n));
	rep(i, 0, n)rep(j, 0, n)cin >> c[i][j];
	ll ans = MOD;
	rep(i, 0, 1) {
		vec<vll> a(n, vll(n));
		rep(j, 0, n)rep(k, 0, n)a[j][k] = c[j][k];
		ll t = 0;
		vll b; b.pub(i);
		rep(j, 0, n)a[j][i] = -1;
		while (b.size() != n) {
			ll m = MOD, kk;
			rep(j, 0, b.size()) {
				rep(k, 0, n) {
					if (a[b[j]][k] != -1 && a[b[j]][k] < m) {
						kk = k;
						m = a[b[j]][kk];
					}
				}
			}
			t += m;
			b.pub(kk);
			rep(j, 0, n)a[j][kk] = -1;
		}
		ans = min(ans, t);
	}
	cout << ans << kai;
}