Hangjian oj-1879

Titulo

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

struct Edge{
	int x,y,w;
}edge[110*110];

int n;
int father[110];

bool cmp(Edge a,Edge b){
	return a.w<b.w;
}

void init(){
	for(int i=1;i<n+1;i++){
		father[i]=i;
	}
}

int findFather(int x){
	int a=x;
	while(father[x]!=x){
		x=father[x];
	}
	while(a!=father[a]){
		int z=a;
		a=father[a];
		father[z]=x;
	}
	return x;
} 

int Union(int a,int b){
	int fa=findFather(a);
	int fb=findFather(b);
	if(fa!=fb){
		father[fa]=fb;
		return 0;
	}else return -1;
}


int Kruskal(int n,int m){
	sort(edge,edge+m,cmp);
	int count1=0;
	int ans=0;
	for(int i=0;i<m;i++){
		//int temp=Union(edge[i].x,edge[i].y);
		if(findFather(edge[i].x)!=findFather(edge[i].y)){
			Union(edge[i].x,edge[i].y);
			ans+=edge[i].w;
			count1++;
			if(count1==n-1)break;
		}
	}
	if(count1==n-1)return ans;
	else return -1;
}
int main(){
	while(1){
		scanf("%d",&n);
		if(n==0)break;
		init();
		int a,b,c,d;
		int num=0;
		for(int i=0;i<n*(n-1)/2;i++){
			scanf("%d%d%d%d",&a,&b,&c,&d);
			edge[num].x=a;
			edge[num].y=b;
			if(d==1){//已建好 
				edge[num].w=0;
			}else{
				edge[num].w=c;
			}
			num++;
		}
		int res=Kruskal(n,n*(n-1)/2);
		printf("%d\n",res);	
	}
}