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| /*
ID: du331691
PROG: picture
LANG: C++
*/
#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<cstdlib>
#include<cmath>
using namespace std;
const int maxn=5003;
const int maxx=10003;
int n;
template<typename T>
void read(T& w)
{
char r;bool f=false;
for(r=getchar();(r<48||r>57)&&r!='-';r=getchar());
if(r=='-')r=getchar(),f=true;
for(w=0;r>=48&&r<=57;r=getchar())w=w*10+r-48;
if(f)w=-w;
}
int toxx[maxx*2+1],toyy[maxx*2+1];
int* tox=&toxx[maxx];
int* toy=&toyy[maxx];
struct EDGE
{
int a,b,p;//a<b
bool isl;
void init(int aa,int bb,int pp,bool isll)
{
a=aa,b=bb,p=pp;
isl=isll;
}
}vedge[maxn*2],hedge[maxn*2];
int vk=0,hk=0;
bool operator<(const EDGE& a,const EDGE& b)
{
if(a.p!=b.p)return a.p<b.p;
if(a.isl!=b.isl)return a.isl;
if(a.a!=b.a)return a.a<b.a;
if(a.b!=b.b)return a.b<b.b;
return false;
}
int sx[maxn*2],sy[maxn*2];
int sxk=0,syk=0;
struct RECTANGLE
{
int ax,ay,bx,by;//lower left, upper right
void input()
{
read(ax),read(ay),read(bx),read(by);
sx[++sxk]=ax,sx[++sxk]=bx;
sy[++syk]=ay,sy[++syk]=by;
}
void addEdge()
{
vedge[++vk].init(ay,by,ax,true);
vedge[++vk].init(ay,by,bx,false);
hedge[++hk].init(ax,bx,ay,true);
hedge[++hk].init(ax,bx,by,false);
}
}rect[maxn];
int d[maxn*2];
//d[i]存放第i条边区间的长度
int f[maxn*2],c[maxn*2];
//f[i] 表示在离散化后第i个点以下的一段边的编号
int idx=0,idy=0;
struct SEQ
{
int l,r,num,mid,len,sum,tag;
void build(int numm,int ll,int rr);
void add(int ll,int rr,int k);
}seq[maxx<<4];
#define root seq[1]
#define lc seq[num<<1]
#define rc seq[num<<1|1]
void SEQ::build(int numm,int ll,int rr)
{
num=numm,l=ll,r=rr,mid=(l+r)>>1;
if(l==r)
{
len=d[l];
sum=tag=0;
}
else
{
lc.build(num<<1,ll,mid);
rc.build(num<<1|1,mid+1,rr);
sum=lc.sum+rc.sum;
}
}
void SEQ::add(int ll,int rr,int k)
{
if(l==r)
{
tag+=k;
sum=int(bool(tag))*len;
}
else
{
if(rr<=mid)
lc.add(ll,rr,k);
else if(ll>mid)
rc.add(ll,rr,k);
else lc.add(ll,mid,k),rc.add(mid+1,rr,k);
sum=lc.sum+rc.sum;
}
}
void input()
{
scanf("%d",&n);
for(int i=1;i<=n;++i)
{
rect[i].input();
rect[i].addEdge();
}
}
typedef unsigned int uint;
const uint uinf=4294967295u;
uint ans=0;
void solve()
{
sort(sy+1,sy+syk+1);
for(int i=1,last=0;i<=syk;++i)
{
if(!toy[sy[i]])
{
toy[sy[i]]=++idy;
f[idy]=idy-1;
c[idy]=idy;
d[idy-1]=sy[i]-last;
last=sy[i];
}
}
root.build(1,1,idy);
sort(vedge+1,vedge+vk+1);
for(int i=1,last=0;i<=vk;++i)
{
if(vedge[i].isl)
root.add(c[toy[vedge[i].a]],f[toy[vedge[i].b]],1);
else
root.add(c[toy[vedge[i].a]],f[toy[vedge[i].b]],-1);
int detal=abs(root.sum-last);
ans+=uint(detal);
last=root.sum;
}
memset(f,0,sizeof(f));
memset(c,0,sizeof(c));
memset(d,0,sizeof(d));
sort(sx+1,sx+sxk+1);
for(int i=1,last=0;i<=sxk;++i)
{
if(!tox[sx[i]])
{
tox[sx[i]]=++idx;
f[idx]=idx-1;
c[idx]=idx;
d[idx-1]=sx[i]-last;
last=sx[i];
}
}
root.build(1,1,idx);
sort(hedge+1,hedge+hk+1);
for(int i=1,last=0;i<=hk;++i)
{
if(hedge[i].isl)
root.add(c[tox[hedge[i].a]],f[tox[hedge[i].b]],1);
else
root.add(c[tox[hedge[i].a]],f[tox[hedge[i].b]],-1);
int detal=abs(root.sum-last);
ans+=uint(detal);
last=root.sum;
}
}
int main()
{
freopen("picture.in","r",stdin);
freopen("picture.out","w",stdout);
input();
solve();
printf("%u\n",ans);
return 0;
}
|
