C :

#include<stdio.h>
int main()
{
	int n,i,j,ii,iii,go,a[100][100],sum,b[1000],bb[1000],min,minnum;
	scanf("%d",&n);
	for(i=1;i<=n;i++)
		for(j=1;j<=n;j++)
			scanf("%d",&a[i][j]);
	b[1]=1;
	sum=0;
	for(i=1;i<n;i++)
	{
		min=minnum=999999;
		for(ii=1;ii<=i;ii++)
			for(j=1;j<=n;j++)
			{
				if(j==b[ii])
					continue;
				go=1;
				for(iii=1;iii<=i;iii++)
				{
					if(b[iii]==j)
						go=0;
				}
				if(go==0)
					continue;
				if(a[b[ii]][j]<min&&a[b[ii]][j]!=0)
				{
					min=a[b[ii]][j];
					minnum=j;
				}
			}
		b[i+1]=minnum;
		sum+=min;
	}
	printf("%d\n",sum);
	return 0;
}

C++ :

#include "stdio.h"
#include "string.h"
#include <algorithm>
using namespace std;
struct number
{
  int s,e,w;
}num[110];
int set[51];
bool cmp(number a,number b)
{
   return a.w<b.w;
}
 int seeks(int i)
 {
     while(set[i]>0)
	 {
	    i=set[i];
	 }
	  return i;
 }
int main(int argc, char* argv[])
{
	int n,i,j,sum,v1,v2,a,k;
	  while(~scanf("%d",&n))
	  { 
		  memset(num,0,sizeof(num));
		  k=1;
	      for(i=1;i<=n;i++)   
		  {
			    for(j=1;j<=n;j++)
				{
					scanf("%d",&a);
					  if(a!=0)
					  {
						  num[k].w=a;
						  num[k].s=i;
					      num[k++].e=j;
					  }
				}
		  }
           memset(set,0,sizeof(set));
		    sort(num+1,num+k+1,cmp);
              i=1;j=1;sum=0;
			   while(i<k&&j<=n)
			   { 
				   v1=seeks(num[i].s);
			       v2=seeks(num[i].e);
				    if(v1!=v2)
					{
					   set[v1]=v2;
					    sum+=num[i].w;
							j++;
					}
					 i++;
			   }
			    printf("%d\n",sum);
	  }
	return 0;
}

Java :

import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int n = input.nextInt();
		int[][] weight = new int[n][n];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				weight[i][j] = input.nextInt();
				if (weight[i][j] == 0)
					weight[i][j] = Integer.MAX_VALUE;
			}
		}
		minTree mintree = new minTree(n);
		mintree.prim(weight, 0);
	}

}

class minTree {
	int vernum;

	public minTree(int n) {
		this.vernum = n;
	}

	public void prim(int[][] weight, int v) {
		int[] visited = new int[vernum];
		int sum = 0;
		int h1 = -1;
		int h2 = -1;
		visited[v] = 1;
		for (int k = 1; k < vernum; k++) {
			int min = Integer.MAX_VALUE;
			for (int i = 0; i < vernum; i++) {
				for (int j = 0; j < vernum; j++) {
					if (visited[i] == 1 && visited[j] == 0 && weight[i][j] < min) {
						min = weight[i][j];
						h1 = i;
						h2 = j;
					}
				}
			}
			visited[h2] = 1;
			sum += min;
		}
		System.out.println(sum);
	}
}