@[lc_lca](/user/120340)
by 忘怀星 @ 2020-05-10 23:59:57
等会，查bug @[忘怀星](/user/305911)
by lc_lca @ 2020-05-11 00:00:41
@[忘怀星](/user/305911) 您是二分吗
by lc_lca @ 2020-05-11 00:03:19
@[lc_lca](/user/120340) 不是，但是我大概知道二分做法
by 忘怀星 @ 2020-05-11 00:03:59
您的主页真好，树形DP题单，顺走了
by 忘怀星 @ 2020-05-11 00:04:39
我很想知道我错在哪里了qwq @[忘怀星](/user/305911)
by lc_lca @ 2020-05-11 00:05:28
qwq
by 忘怀星 @ 2020-05-11 00:06:28
```cpp
#include<iostream>
#include<algorithm>
#include<math.h>
using namespace std;
int s,p;
double x[510],y[510];
int f[510];
int findx(int x)
{
if(x==f[x]) return x;
return f[x]=findx(f[x]);
}
void init()
{
for(int i=1;i<=500;i++) f[i]=i;
}
int main()
{
cin>>s>>p;
for(int i=1;i<=p;i++)
{
cin>>x[i]>>y[i];
}
double l=0,r=100000000;
double ans=0;
while(l<=r)
{
double mid=(l+r)/2;
//cout<<mid<<endl;
init();
for(int i=1;i<=p;i++)
{
//double xx=x[i],yy=y[i];
for(int j=1;j<=p;j++)
{
if(j==i) continue;
if(double(x[i]-x[j])*(x[i]-x[j])<=mid && double(y[i]-y[j])*(y[i]-y[j])<=mid)
{
int fx=findx(i);
int fy=findx(j);
if(fx!=fy)
f[fx]=fy;
}
}
}
int sum=0;
for(int i=1;i<=p;i++)
{
if(f[i]==i) sum++;
}
if(sum<=s)
{
ans=mid;
r=mid-1;
}
else l=mid+1;
}
printf("%.2f\n",(double)sqrt((double)ans));
return 0;
}
```
by lc_lca @ 2020-05-11 00:06:28
wozhidaol
by lc_lca @ 2020-05-11 00:08:27
您这个……二分了个啥？
by 忘怀星 @ 2020-05-11 00:08:43