UVa 11631 - Dark roads

#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>

using namespace std;

typedef struct d_node
{
	int point1;
	int point2;
	int weight;
}enode;
enode edge[200002];

//union_set
int sets[200002];
int rank[200002];

void set_inital( int a, int b )
{
	for ( int i = a ; i <= b ; ++ i ) {
		rank[i] = 0;
		sets[i] = i;
	}
}

int  set_find( int a )
{
	if ( a != sets[a] )
		sets[a] = set_find( sets[a] );
	return sets[a];
}

void set_union( int a, int b )
{
	if ( rank[a] < rank[b] )
		sets[a] = b;
	else {
		if ( rank[a] == rank[b] )
			rank[a] ++;
		sets[b] = a;
	}
}
//end_union_set

int cmp_e( enode a, enode b )
{
	return a.weight < b.weight;
}

long long kruskal( int n, int m )
{
	sort( edge, edge+m, cmp_e );
	
	set_inital( 0, n );
	long long sum = 0LL;
	for ( int i = 0 ; i < m ; ++ i ) {
		int A = set_find( edge[i].point1 );
		int B = set_find( edge[i].point2 );
		if ( A != B ) { 
			set_union( A, B );
			sum += edge[i].weight+0LL;
		}
	}
	return sum;
}

int main()
{
	int n,m,a,b,c; 
	while ( scanf("%d%d",&n,&m) && n+m ) {
		long long sum = 0LL;
		for ( int i = 0 ; i < m ; ++ i ) {
			scanf("%d%d%d",&a,&b,&c);
			edge[i].point1 = a;
			edge[i].point2 = b;
			edge[i].weight = c;
			sum += c+0LL;
		}
		
		printf("%lld\n",sum-kruskal( n, m ) );
	}
	return 0;
}