bzoj 4749: [Usaco2016 Dec]Moocast dfs

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很水的dfs题

n^2的dfs，把每个点都当作起点跑一遍，最后取max

代码：

#include<iostream>#include<cstdio>#include<cmath>#include<cstring>using namespace std;struct node{int x,y,p;};int n;node a[220];bool f[220];int ans=0;double cal(int x,int y){double d=sqrt((a[x].x-a[y].x)*(a[x].x-a[y].x)*1.0+(a[x].y-a[y].y)*(a[x].y-a[y].y)*1.0);return d;}int dfs(int x){f[x]=true;int sum=1;for(int i=0; i<n; i++){if(f[i] || x==i)continue;if(cal(i,x)<=a[x].p*1.0)sum+=dfs(i);}return sum;}int main(){scanf("%d",&n);for(int i=0; i<n; i++)scanf("%d%d%d",&a[i].x,&a[i].y,&a[i].p);for(int i=0; i<n; i++){memset(f,0,sizeof(f));ans=max(ans,dfs(i));}printf("%d\n",ans);return 0;}