求助wa20

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

using namespace std;

int n,m,k,fa[10000001];

struct Edge{
	int x,y,v,id;
	bool operator < (const Edge &b) const {
		if(v==b.v)return id<b.id;
		return v<b.v;
	}
}e[10000001];

int find(int x){
	if(x==fa[x])return x;
	else return fa[x]=find(fa[x]);
}

void merge(int x,int y){
	fa[x]=y;
}

int main(){
	scanf("%d%d%d",&n,&m,&k);
	for(int i=1;i<=m;i++){
		scanf("%d%d%d%d",&e[i].x,&e[i].y,&e[i].v,&e[i].id);
		e[i].x++;
		e[i].y++;
	}
	int l=-100,r=100,last=0,ans=0;
	while(l<r){
		int mid=(l+r)>>1,col=n-1,tot;ans=0;
		for(int i=1;i<=n;i++)fa[i]=i;
		for(int i=1;i<=m;i++){
			if(!e[i].id)e[i].v+=mid-last;
		}
		sort(e+1,e+m+1);
		col=n-1;
		for(int i=1;i<=m;i++){
			int x=e[i].x;
			int y=e[i].y;
			int fx=find(x),fy=find(y);
			if(fx!=fy){
				col-=e[i].id;
				ans+=e[i].v;
				merge(fx,fy);
				tot++;
				if(tot==n-1)break;
			}
		}
		last=mid;
		if(col>k){
			l=mid+1;
		}else {
			r=mid;
		}
	}
	printf("%d",ans-k*l);
	return 0;
}