codevs3044 线段树+扫描线

3044 矩形面积求并

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 // #pragma comment(linker, "/STACK:1024000000,1024000000")
 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <sstream>
 #include <string>
 #include <algorithm>
 #include <list>
 #include <map>
 #include <vector>
 #include <queue>
 #include <stack>
 #include <cmath>
 #include <cstdlib>
 // #include <conio.h>
 using namespace std;
 #define clc(a,b) memset(a,b,sizeof(a))
 #define inf 0x3f3f3f3f
 #define lson l,mid,rt<<1
 #define rson mid+1,r,rt<<1|1
 const int N = ;
 const int MOD = 1e9+;
 #define LL long long
 #define mi() (l+r)>>1
 double const pi = acos(-);

 // inline int r() {
 //     int x=0,f=1;char ch=getchar();
 //     while(ch>'9'||ch<'0') {if(ch=='-') f=-1;ch=getchar();}
 //     while(ch>='0'&&ch<='9') { x=x*10+ch-'0';ch=getchar();}return x*f;
 // }
 int n;
 double hashh[N<<];
 double sum[N<<];
 int color[N<<];
 struct Edge{
      double x1,x2,y;
      int flag;
      bool operator < (const Edge &a) const{
          return y<a.y;
      }
 }e[N<<];

 int b_s(double x){
      int l=,r=*n;
      int mid;
      while(l<=r){
           mid=(l+r)>>;
           if(hashh[mid]==x) return mid;
           else if(hashh[mid]<x) l=mid+;
           else r=mid-;
      }
 }

 void pushdown(int rt,int l,int r){
      if(color[rt]) sum[rt]=hashh[r+]-hashh[l];
      else if(l==r) sum[rt]=;
      else sum[rt]=sum[rt<<]+sum[rt<<|];
 }

 void update(int l,int r,int rt,int x,int y,int f){
      if(x==l&&y==r){
           color[rt]+=f;
           pushdown(rt,l,r);
           return;
      }
      int mid=mi();
      if(y<=mid) update(l,mid,rt<<,x,y,f);
      else if(x>mid) update(mid+,r,rt<<|,x,y,f);
      else {
          update(l,mid,rt<<,x,mid,f);
          update(mid+,r,rt<<|,mid+,y,f);
      }
      pushdown(rt,l,r);
 }
 int main(){
      // int n;
      while(scanf("%d",&n)){
          if(n==)
             break;
          clc(color,);
          clc(sum,);
          double x1,x2,y1,y2;
          for(int i=;i<=n;i++){
              scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
              e[i*-].x1=e[i*].x1=x1;
              e[i*-].x2=e[i*].x2=x2;
              e[i*-].y=y1;e[i*].y=y2;
              e[i*-].flag=;e[i*].flag=-;
              hashh[i*-]=x1;hashh[i*]=x2;
          }
          sort(e+,e++*n);
          sort(hashh+,hashh++*n);
          double ans=;
          for(int i=;i<=*n;i++){
              int l=b_s(e[i].x1),r=b_s(e[i].x2)-;
              // cout<<"l:"<<l<<" "<<"r:"<<r<<endl;
              if(l<=r) update(,*n,,l,r,e[i].flag);
              // cout<<"sum[1]"<<sum[1]<<endl;
              ans+=sum[]*(e[i+].y-e[i].y);
          }
          printf("%.2f\n",ans);
      }
      return ;
 }