1001 The Cats' Feeding Spots （2015年北京赛区网络赛A题）

来源：互联网发布：罗技淘宝编辑：程序博客网时间：2024/04/30 13:04

1.题目描述：点击打开链接

2.解题思路：本题需要分三种情况讨论：(1) n<m (2) n==m (3) n>m。首先枚举圆心，然后计算其他点相对于该圆心的距离，排序后根据情况来讨论即可。

3.代码：

#include<iostream>#include<algorithm>#include<cassert>#include<string>#include<sstream>#include<set>#include<bitset>#include<vector>#include<stack>#include<map>#include<queue>#include<deque>#include<cstdlib>#include<cstdio>#include<cstring>#include<cmath>#include<ctime>#include<cctype>#include<complex>#include<functional>#pragma comment(linker, "/STACK:1024000000,1024000000")using namespace std;#define me(s)  memset(s,0,sizeof(s))#define rep(i,n) for(int i=0;i<(n);i++)typedef long long ll;typedef unsigned int uint;typedef unsigned long long ull;typedef pair <ll, ll> P;const int N=100+10;const int INF=1000000000;double x[N],y[N];const double eps=1e-10;int dcmp(double x){    if(fabs(x)<eps)return 0;    return x<0?-1:1;}double dist[N];double dis(double dx,double dy){    return sqrt(dx*dx+dy*dy);}int n,m;int calc(int s){    me(dist);    int idx=1;    for(int i=0;i<m;i++)        if(i!=s)        dist[idx++]=dis(x[i]-x[s],y[i]-y[s]);    sort(dist,dist+idx);    if(n<m)    {        int upp=ceil(dist[n-1]);        if(dcmp((double)upp-dist[n-1])==0)        {            if(dcmp(dist[n]-(double)upp-1.0)<=0)return INF;            else return upp+1;        }        else        {            if(dcmp(dist[n]-(double)upp)<=0)return INF;            else return upp;        }    }    else if(n==m)    {        int upp=ceil(dist[n-1]);        if(dcmp((double)upp-dist[n-1])==0)return upp+1;        else return upp;    }    else return INF;}int main(){    int T;    scanf("%d",&T);    while(T--)    {        scanf("%d%d",&m,&n);        for(int i=0;i<m;i++)            scanf("%lf%lf",&x[i],&y[i]);        int ans=INF;        for(int i=0;i<m;i++)        {            ans=min(ans,calc(i));        }        if(ans==INF)puts("-1");        else printf("%d\n",ans);    }}

0 0