UVA

题意:给你n个矩形的中心和中心到边的距离让你求面积并

题解:套一下模板就好了

#include<cstdio>#include<iostream>#include<cstring>#include<algorithm>#include<cmath>using namespace std;const int maxn = 2e3+5; struct node{    double x1,x2,y;    int f;}E[2*maxn];double x[2*maxn];struct tree{    double l,r;    int flag;    int cover;}t[maxn*8];bool cmp(node a,node b){    return a.y < b.y;}void built(int i,int l,int r){    t[i].l = x[l],t[i].r = x[r];    t[i].cover = t[i].flag = 0;    if(l+1 >= r){        t[i].flag = 1;        return ;    }    int mid = (l+r)/2;    built(2*i,l,mid);    built(2*i+1,mid,r);}double update(int i,double l,double r,double y,int f){    if(t[i].flag){         if(t[i].r <= r && t[i].l >= l)            t[i].cover += f;        if(t[i].cover)            return t[i].r - t[i].l;        else{            return 0;        }    }    double s1 = update(2*i,l,r,y,f);    double s2 = update(2*i+1,l,r,y,f);    return s1+s2;}int main(){    int t = 1;    int n;    double x1,y1,r;    while(scanf("%d",&n) && n){        int m = 1;        int d = 0;        for(int i = 1; i <= n; i++){            scanf("%lf%lf%lf",&x1,&y1,&r);            if(fabs(r-0)<=1e-6){            d++;            continue;}            x[m-1] = E[m].x1 = E[m+1].x1 = x1-r;            x[m] = E[m].x2 = E[m+1].x2 = x1+r;            E[m].f = 1;            E[m+1].f = -1;            E[m+1].y = y1+r;            E[m].y = y1-r;            m += 2;        }        n-=d;        sort(x,x+2*n);        sort(E+1,E+1+2*n,cmp);        int k = 1;        for(int i = 1; i < 2*n; i++)            if(x[i] != x[i-1])                x[k++] = x[i];        built(1,0,k-1);        double area = 0;        for(int i = 1; i < 2*n; i++)            area += (E[i+1].y - E[i].y)*update(1,E[i].x1,E[i].x2,E[i].y,E[i].f);        printf("%d %.2lf\n",t++,area);    }    return 0;}