luogu【P1378】油滴拓展 計算幾何？

手賤忘記在ans+0.5那裏加上括號坑了·好久。

期末考試完回來刷刷水題找下手感。

百度之星的T居然還沒到。。。。。。。。

/* ***********************************************
Author        :BPM136
Created Time  :2016/7/7 10:40:46
File Name     :A.cpp
************************************************ */

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<iomanip>
#include<bitset>
#include<queue>
#include<ctime>
#include<set>
#include<utility>
#include<vector>
#include<functional>
#include<numeric>
#include<memory>
#include<iterator>
#define LL long long
#define DB double
#define LB long double
#define UL unsigned long
#define ULL unsigned long long
#define pb push_back
#define popb pop_back
#define get(a,i) a&(1<<(i-1))
#define PAU putchar(32)
#define ENT putchar(10)
#define clr(a,b) memset(a,b,sizeof(a))
#define fo(_i,_a,_b) for(int _i=_a;_i<=_b;_i++)
#define fd(_i,_a,_b) for(int _i=_a;_i>=_b;_i--)
#define efo(_i,_a) for(int _i=last[_a];_i!=0;_i=e[_i].next)
#define file(x) freopen(#x".in","r",stdin),freopen(#x".out","w",stdout);
#define mkd(x) freopen(#x".in","w",stdout);
#define setlargestack(x) int size=x<<20;char *p=(char*)malloc(size)+size;__asm__("movl %0, %%esp\n" :: "r"(p));
#define end system("pause")
using namespace std;
LL read()
{
         LL f=1,d=0;char s=getchar();
         while (s<48||s>57){if (s==45) f=-1;s=getchar();}
         while (s>=48&&s<=57){d=d*10+s-48;s=getchar();}
         return f*d;
}
LL readln()
{
       LL f=1,d=0;char s=getchar();
       while (s<48||s>57){if (s==45) f=-1;s=getchar();}
       while (s>=48&&s<=57){d=d*10+s-48;s=getchar();}
       while (s!=10) s=getchar();
       return f*d;
}
inline void write(LL x)
{
    if(x==0){putchar(48);return;}if(x<0)putchar(45),x=-x;
    int len=0,buf[20];while(x)buf[len++]=x%10,x/=10;
    for(int i=len-1;i>=0;i--)putchar(buf[i]+48);return;
}
inline void writeln(LL x){write(x);ENT;}

const int N = 10;

struct point {
	int x,y;
}p[N];

point po(int x,int y) {
	point ret;
	ret.x=x,ret.y=y;
	return ret;
}

DB dis(point a,point b) {
	point ret;
	ret.x=a.x-b.x;
	ret.y=a.y-b.y;
	int anss=ret.x*ret.x+ret.y*ret.y;
	return (DB)sqrt(anss);
}

struct circle {
	int x,y;
	DB r;
	void clear() {
		x=y=r=0.0;
	}
	DB area() {
		DB ret=3.1415926535;
		ret=ret*r*r;
		return ret;
	}
	void OUT() {
		cout<<x<<' '<<y<<' '<<r<<endl;
	}
};

int n;
int xn1,yn1,xn2,yn2;

void init() {
	n=read();
	xn1=read(),yn1=read();
	xn2=read(),yn2=read();
	fo(i,1,n) {
		p[i].x=read(),p[i].y=read();
	}
}

bool v[N];
int c[N];

DB ans=0.0,anss,chu;

circle a[N];

DB fmin(DB x,DB y) {
	if(x-y<0) return x;
	return y;
}

DB fabs(DB x) {
	if(x<0) return -x;
	return x;
}

DB calc(int x,int y,circle t) {
	DB ret=dis(po(x,y), po(t.x,t.y));
	ret=ret-t.r;
	if(ret<0) ret=0.0;
	return ret;
}

bool found(int x,int y) {
	int kx=min(xn1,xn2),sx=max(xn1,xn2);
	int ky=min(yn1,yn2),sy=max(yn1,yn2);
	if(kx>x||x>sx) return 1;
	if(ky>y||y>sy) return 1;
	return 0;
}

void ins(int k,int x) {
	int zx=p[x].x,zy=p[x].y;
	a[k].x=zx,a[k].y=zy;
	DB R=0.0;
	R=min( min(abs(xn1-zx),abs(xn2-zx)), min(abs(yn1-zy),abs(yn2-zy)) );
	fo(i,1,k-1) R=fmin(R,calc(zx,zy,a[i]));
	if(found(zx,zy)) R=0.0;
	a[k].r=R;
}

void check() {
	anss=chu;
	fo(i,1,n) a[i].clear();
	fo(i,1,n) ins(i,c[i]);
//	fo(i,1,n) write(c[i]),PAU; ENT;
//	fo(i,1,n) a[i].OUT(); 
	fo(i,1,n) anss=anss-a[i].area();
//	writeln(anss); ENT;
	if(anss<ans) ans=anss;
}

void dfs(int x) {
	if(x>n) {
		check();
		return ;
	}
	fo(i,1,n) {
		bool flag=v[i];
		if(!flag) {
			c[x]=i;v[i]=1;
			dfs(x+1);
			c[x]=0;v[i]=0;
		}
	}
}

void work() {
	chu=fabs(xn1-xn2)*fabs(yn1-yn2)*1.0;
	clr(v,0); clr(c,0); ans=chu;
	dfs(1);
	writeln((int)(ans+0.5));
}

int main() {
	file(A);
	init();
	work();
	return 0;
}