poj 1177 picture 线段树

调了两天。。。最后那天晚上线段树按[1,2)写的很容易就对了。。

/*
ID:autoacd1
PROG:picture
LANG:C++
*/
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
#define MAX 21000
#include<cmath>

using namespace std;

struct wbysr
{
	int x1,y1,x2,y2,d;
}x[10000+4],y[10000+4];

int n,i,ans_x=0,ans_y=0,ori=0;
int l[4*MAX],r[4*MAX],f[4*MAX],len[4*MAX];

bool cmp_x(wbysr a1,wbysr a2)
{
	return (a1.y1>a2.y1)||(a1.y1==a2.y1&&a1.d>a2.d);
}

bool cmp_y(wbysr a1,wbysr a2)
{
	return(a1.x1>a2.x1)||(a1.x1==a2.x1&&a1.d>a2.d);
}

void build(int x,int la,int ra)
{
	l[x]=la;
	r[x]=ra;
	f[x]=0;
	len[x]=0;
	if(la==ra-1)
	  return;
	int mid=(la+ra)/2;
	build(2*x,la,mid);
	build(2*x+1,mid,ra);
}

void insert(int x,int la,int ra,int num)
{    
    if(ra<=l[x]||la>=r[x])
	  return;
	if(l[x]>=la&&r[x]<=ra&&f[x]+num>=0)
	  {
	     f[x]+=num;
		 if(f[x]>0)
            len[x]=r[x]-l[x];
		else
         {
		   if(l[x]<r[x]-1)
		     len[x]=len[2*x]+len[2*x+1];
		    else
		      len[x]=0;
         }		
		 return;	  	
	  }	
	f[2*x]+=f[x];
	f[2*x+1]+=f[x];
	f[x]=0;	
	if(f[2*x])
	   len[2*x]=r[2*x]-l[2*x];
/*	else
         {
		   if(l[2*x]<r[2*x]-1)
		     len[2*x]=len[2*2*x]+len[2*(2*x)+1];
		    else
		      len[2*x]=0;
         }	*/
	if(f[2*x+1])
	   len[2*x+1]=r[2*x+1]-l[2*x+1];
/*	else
         {
		   if(l[2*x+1]<r[2*x+1]-1)
		     len[2*x+1]=len[2*(2*x+1)]+len[2*(2*x+1)+1];
		    else
		      len[(2*x+1)]=0;
         }*/
	insert(2*x,la,ra,num);
	insert(2*x+1,la,ra,num);
	
	if(f[x])
            len[x]=r[x]-l[x];
		else
         len[x]=len[2*x]+len[2*x+1];
	return;
}

int main()
{
    {    
    //freopen("1.out","w",stdout);
//    freopen("picture.in","r",stdin);
  //  freopen("picture.out","w",stdout);
  cin>>n;
	for(i=1;i<=2*n;i+=2)
	 {
	 	int x1,y1,x2,y2;
	 	scanf("%d%d%d%d",&x1,&y1,&x2,&y2);	   
//	/*
	    x1+=10005;
	 	x2+=10005;
	 	y2+=10005;
	 	y1+=10005;  
//	 	*/
	 	
	 	//x
	 	x[i].x1=x1;
	 	x[i].y1=y1;
	 	x[i].x2=x2;
		x[i].y2=y1;	 	
	 	x[i].d=-1;
	 	
	 	i++;
	 	x[i].x1=x1;
	 	x[i].y1=y2;
	 	x[i].x2=x2;
		x[i].y2=y2;	 	
	 	x[i].d=1;
	 	
	 	//y
	 	i--;
	 	y[i].x1=x1;
	 	y[i].y1=y1;
	 	y[i].x2=x1;
		y[i].y2=y2;	 	
	 	y[i].d=-1;
	 	i++;
	 	
	 	y[i].x1=x2;
	 	y[i].y1=y1;
	 	y[i].x2=x2;
		y[i].y2=y2;	 	
	 	y[i].d=1;
	 	i--;
	 }
	
	//x!!!
    sort(x+1,x+1+n+n,cmp_x);   
    build(1,1,MAX+4);
   for(i=1;i<=2*n;i++)   
       {
       	//cout<<"-------------------------------------------"<<i<<endl;
       	 insert(1,x[i].x1,x[i].x2,x[i].d);       	
         if(x[i].y1!=x[i+1].y1||x[i].d!=x[i+1].d)
		 {
		    ans_x+=abs(len[1]-ori);
       	    ori=len[1];
		 } 
       	 //   cout<<"___"<<x[i].x1<<' '<<x[i].x2<<' '<<x[i].d<<' '<<len[1]<<' '<<ans_x<<endl;   
		/*    	  
       	    cout<<"-________________________________"<<endl;
       	    for(int j=1;j<=136;j++)
               cout<<j<<"   "<<l[j]<<"   "<<r[j]<<"   "<<len[j]<<"   "<<f[j]<<endl;  
		//  */
       }
 //   cout<<"_____"<<ans_x<<endl;    
    
   
   //y!!!
  	memset(l,0,sizeof(l));
	memset(r,0,sizeof(r));
	memset(f,0,sizeof(f));	
	memset(len,0,sizeof(len));      
    sort(y+1,y+1+n+n,cmp_y);   
    build(1,1,MAX+4);
    for(i=1;i<=2*n;i++)   
       {
       	//cout<<"-------------------------------------------"<<i<<endl;
       	 insert(1,y[i].y1,y[i].y2,y[i].d);  		    	 		 
	   if(y[i].x1!=y[i+1].x1||y[i].d!=y[i+1].d)     	 
       	{
       	 	ans_y+=abs(len[1]-ori);
       	    ori=len[1];
       	}
     //  	    cout<<"_____"<<y[i].y1<<' '<<y[i].y2<<' '<<y[i].d<<' '<<len[1]<<' '<<ans_y<<endl;       	  
      /* 	    cout<<"-________________________________"<<endl;
       	  for(int j=1;j<=49;j++)
              cout<<j<<"   "<<l[j]<<"   "<<r[j]<<"   "<<len[j]<<"   "<<f[j]<<endl;  
       	 */
       }
 //   cout<<"_____"<<ans_y<<endl;
   
    cout<<ans_x+ans_y<<endl;
    }
    return 0;
}