度度熊保护村庄 HDU

点在向量同侧的话就把向量的两个点连一条路,最后跑一次floyd求到自己的最小环

不知道为什么500^3跑得飞快

#include<bits/stdc++.h>
#include<stdio.h>
#include<algorithm>
#include<queue>
#include<string.h>
#include<iostream>
#include<math.h>
#include<set>
#include<map>
#include<vector>
#include<iomanip>
using namespace std;
#define ll long long
#define pb push_back
#define FOR(a) for(int i=1;i<=a;i++)
const int inf=0x3f3f3f3f;
const int maxn=1e6+9; 
const int mod=1e9+7;

struct Point{
	int x,y;
	Point operator -(const Point &b)const{
		Point c;c.x=x-b.x;c.y=y-b.y;return c;
	}
	double operator *(const Point &b)const{
		return x*b.y-y*b.x;
	}
};

Point h[505],s[505];
int n,m,ans,G[505][505];
inline bool judge(Point x,Point y,Point z){
	if((x.x<z.x&&y.x<z.x)||(x.y<z.y&&y.y<z.y)||(x.x>z.x&&y.x>z.x)||
			(x.y>z.y&&y.y>z.y))return 1;
	return 0;
}

int main(){
	while(~scanf("%d",&n)){
		memset(G,0x3f,sizeof G);
		for(int i=1;i<=n;i++)scanf("%d%d",&h[i].x,&h[i].y);
		scanf("%d",&m);
		FOR(m)scanf("%d%d",&s[i].x,&s[i].y);
		int flag;
		FOR(m){
			for(int j=1;j<=m;j++){
				flag=1;
				for(int k=1;k<=n;k++){
					if((s[i]-s[j])*(s[i]-h[k])<0||
					(s[i]-s[j])*(s[i]-h[k])==0&&judge(s[i],s[j],h[k])){
						//右侧或延长线上
						flag=0;break;
					}
				}
				if(flag){
					G[i][j]=1;
				}
			}
		}
		ans=inf;
		for(int k=1;k<=m;k++){
			for(int i=1;i<=m;i++){
				if(G[i][k]==inf)continue;
				for(int j=1;j<=m;j++)G[i][j]=min(G[i][j],G[i][k]+G[k][j]);
			}
		}
		for(int i=1;i<=m;i++)ans=min(ans,G[i][i]);
		if(ans>m)printf("ToT
");
		else printf("%d
",m-ans);
	}
}


原文地址:https://www.cnblogs.com/Drenight/p/8611286.html