标签:pac div using max scanf highlight can namespace cpp
最小生成树或者二分都行,但是最小生成树会好写一些~
Code:
#include <bits/stdc++.h> #define ll long long #define N 1000005 #define setIO(s) freopen(s".in","r",stdin) using namespace std; ll x[N],y[N]; int p[N]; struct Edge { int u,v; ll c; }e[N]; bool cmp(Edge a,Edge b) { return a.c<b.c; } int find(int x) { return p[x]==x?x:p[x]=find(p[x]); } int main() { // setIO("input"); int n,k,i,j,cnt=0,jj; scanf("%d%d",&n,&k); for(i=1;i<=n;++i) scanf("%lld%lld",&x[i],&y[i]); for(i=1;i<=n;++i) p[i]=i; for(i=1;i<=n;++i) { for(j=i+1;j<=n;++j) { ++cnt; e[cnt].u=i; e[cnt].v=j; e[cnt].c=(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]); } } sort(e+1,e+1+cnt,cmp); ll lst=0; int pp=n; lst=e[1].c; for(i=1;i<=cnt;i=j) { for(j=i;j<=cnt&&e[j].c==e[i].c;++j); for(jj=i;jj<j;++jj) { int u=e[jj].u; int v=e[jj].v; u=find(u), v=find(v); if(u!=v) p[u]=v, --pp; // printf("%d %d %lld\n",e[jj].u,e[jj].v,e[jj].c); } if(pp>=k) { lst=max(lst,e[j].c); } else { break; } } // printf("%lld\n",lst); printf("%.2f\n",sqrt(lst)); return 0; }
luogu 4047 [JSOI2010]部落划分 最小生成树
标签:pac div using max scanf highlight can namespace cpp
原文地址:https://www.cnblogs.com/guangheli/p/11602806.html