C :

#include<stdio.h>
#include<string.h>
#include<stdlib.h>


int main()
{
    int t,n,e,a,b,k,i,j,temp,sum,len,min;
	int map[500][500],arr[500],node[500];
    for(scanf("%d",&t);t>0;t--)
	{
		memset(arr,0,500*sizeof(int));
		for(i=0;i<n;i++)
			memset(map,-1,n*sizeof(int));
		for(scanf("%d%d",&n,&e),i=0;i<e;i++)
		{
		   scanf("%d%d%d",&a,&b,&k);
		   map[a][b]=k;
		   map[b][a]=k;
		   if(i==0)
		   {
		     arr[a]=-1;node[0]=a;
		   }
		}
		for(temp=0,min=1000,sum=0,i=0,len=1;i<len&&len!=n;i++)
		{  
			
		   for(j=0;j<n;j++)
		   {
		      if(map[node[i]][j]>=0&&arr[j]!=-1&&min>map[node[i]][j])
			  {
			     min=map[node[i]][j];temp=j;
			  }
		   }
		  if(i==len-1)
		  {
			  sum+=min;
			  arr[temp]=-1;
			  node[len]=temp;
			  len++;i=-1;
			  min=1000;
		  }
		  
		}
		printf("%d\n",sum);
	}
	return 0;
}

C++ :

#include<stdio.h>
#include<algorithm>
using namespace std;

struct vi
{
	int start;
	int end;
	int cost;
}edge[130000],et;

int p[500];

int Find(int n)
{
	return n==p[n]?n:p[n]=Find(p[n]);
}

bool cmp(vi a,vi b)
{
	return a.cost<b.cost;
}

int main()
{
	int t,n,e,i,k,sum,ST,EN;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d%d",&n,&e);
		for(i=0;i<n;i++)
			p[i]=i;
		for(k=i=0;i<e;i++)
		{
			scanf("%d%d%d",&et.start,&et.end,&et.cost);
			if(et.cost==0)
				p[Find(et.start)]=Find(et.end);
			else
				edge[k++]=et;
		}
		sort(edge,edge+k,cmp);
		for(sum=i=0;i<k;i++)
		{
			ST=Find(edge[i].start);
			EN=Find(edge[i].end);
			if(ST!=EN)
			{
				p[ST]=EN;
				sum+=edge[i].cost;
			}
		}
		printf("%d\n",sum);
	}
	return 0;
}

Java :

import java.util.*;
public class Main {
	private static Scanner in;

	public static void main(String[] args) {
		in = new Scanner(System.in);
		int i,t,n,e,j,f,o,h,g,temp1,temp2,current;
		int a,b,m,mm,k,min,mincost,minIndex=0;
		int[][] nextArray;
		ArrayList<Integer> U = new ArrayList<Integer>();
		ArrayList<Integer> V = new ArrayList<Integer>();
		t = in.nextInt();
		for(i = 1;i <= t;i++){
			mincost = 0;
			U.clear();
			V.clear();
			n = in.nextInt();
			e = in.nextInt();
			nextArray = new int[n][n];
			for( m = 0;m < n;m++)
				for( mm = 0;mm < n;mm++)
					nextArray[m][mm]=-1;
			for( j = 0;j < e;j++) {
				a = in.nextInt();
				b = in.nextInt();
				k = in.nextInt();
				nextArray[a][b]=k;
				nextArray[b][a]=k;
			}
			U.add(0);
			for (f = 1;f < n;f++)
				V.add(f);
			for( o = 1;o < n;o++) {
				min = 1000;
				for( h = 0;h < U.size();h++) {
					    temp1=U.get(h);
					for(g=0;g < V.size();g++) {
					    temp2 = V.get(g);
						current = nextArray[temp1][temp2];
						if(current != -1 && current < min) {
							min = current;
							minIndex = g;
						}
					}
				}
				mincost += min;
				U.add(V.get(minIndex));
				V.remove(minIndex);
			}
			System.out.println(mincost);
		}

	}
}