【bzoj2654]】tree

#include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;

typedef long long LL;

#define N 100010

struct Node
{
int x,y,z,c;
}e
,a
;

int n,m,need;

LL ans,cnt,tot;

int l,r,mid;

int f
;

int cmp(Node a,Node b)
{
return a.z==b.z ? a.c<b.c : a.z<b.z;
}

int find(int x)
{
return f[x]!=x ? f[x]=find(f[x]) : f[x];
}

void kruskal()
{
cnt=0,ans=0;
int k=0;
for (int i=1;i<=n;i++)
f[i]=i;
for (int i=1;k<n-1;i++)
{
int fa=find(e[i].x);
int fb=find(e[i].y);
if (fa!=fb)
{
f[fa]=fb;
ans+=e[i].z;
k++;
if (!e[i].c)
cnt++;
}
}
}

int main()
{
scanf("%d%d%d",&n,&m,&need);
for (int i=1;i<=m;i++)
scanf("%d%d%d%d",&a[i].x,&a[i].y,&a[i].z,&a[i].c),a[i].x++,a[i].y++;
l=-1010,r=1010;
while (l<=r)
{
mid=(l+r)>>1;
for (int i=1;i<=m;i++)
e[i]=a[i];
for (int i=1;i<=m;i++)
if (!e[i].c)
e[i].z-=mid;
sort(e+1,e+m+1,cmp);
kruskal();
if (cnt<need)
l=mid+1;
else
r=mid-1,tot=ans+need*mid;
}
printf("%lld\n",tot);
return 0;
}