代码

#include <stdio.h>
typedef long long ll;
static int fa[1005];
static ll x[1005],y[1005],z[1005];
static int find(int a){ while(fa[a]!=a){ fa[a]=fa[fa[a]]; a=fa[a]; } return a; }
int main(){
    int T; if(scanf("%d",&T)!=1) return 0;
    while(T--){
        int n; ll h,r; scanf("%d %lld %lld",&n,&h,&r);
        for(int i=0;i<n;i++) scanf("%lld %lld %lld",&x[i],&y[i],&z[i]);
        for(int i=0;i<=n+1;i++) fa[i]=i;
        ll rr=4*r*r;
        for(int i=0;i<n;i++){
            if(z[i]-r<=0) fa[find(i)]=find(n);
            if(z[i]+r>=h) fa[find(i)]=find(n+1);
            for(int j=0;j<i;j++){
                ll dx=x[i]-x[j], dy=y[i]-y[j], dz=z[i]-z[j];
                if(dx*dx+dy*dy+dz*dz<=rr) fa[find(i)]=find(j);
            }
        }
        printf("%s\n", find(n)==find(n+1)?"Yes":"No");
    }
    return 0;
}

评测结果