UVa221 Urban Elevations

暴力枚举判断是否可见。

注意特判几栋房子一起遮挡一栋房子的情况。

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
using namespace std;
const int mxn=1010;
struct building{
    int x,y,w,h;
    int id;
}a[mxn],b[mxn];
int cmp(const building c,const building d){
    return (c.x<d.x)||(c.x==d.x && c.y<d.y);
}
int n,m;
bool check(int t){
    int pos=a[t].x;
    int cnt=0;
    for(int i=1;i<=n;i++){
        if(i==t)continue;
        if(a[i].y<a[t].y && a[i].x<=a[t].x && a[i].x+a[i].w>=a[t].x+a[t].w && a[i].h>=a[t].h)return false;
        if(a[i].y<a[t].y && a[i].h>=a[t].h && a[i].x<=pos && a[i].x+a[i].w>=pos)pos=max(pos,a[i].x+a[i].w);
    if(pos<a[t].x+a[t].w)return true;
    return false;
}
int ans[mxn],top=0;
void solve(){
    for(int i=1;i<=n;i++)
        if(check(i))ans[++top]=a[i].id;
    return;
}
int main(){
    int i,j;
    int cas=0;
    while(scanf("%d",&n) && n){
        if(cas)printf("
");
        top=0;
        for(i=1;i<=n;i++){
            scanf("%d%d%d%*d%d",&a[i].x,&a[i].y,&a[i].w,&a[i].h);
            a[i].id=i;
        }
        sort(a+1,a+n+1,cmp);
        solve();
        printf("For map #%d, the visible buildings are numbered as follows:
",++cas);
        for(i=1;i<top;i++)printf("%d ",ans[i]);
        printf("%d",ans[top]);
        printf("
");
    }
    return 0;
}