OJ-Problems-Source/HDOJ/1828_autoAC.cpp

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C++
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#include<algorithm>
#include<iostream>
#include<cstdio>
const int maxn=5010;
const int CONST=10001;
using namespace std;
struct Line
{
int l,r,h;
char lab;
}line[maxn*2];
struct node
{
int lc,rc,cnt,len,num;
char rn,ln;
}tree[maxn*2*4];
int n,pos[maxn*2],m,ans,tmpl,tmpr;
int abs(int a){return a>0?a:-a;}
bool cmp(Line a,Line b)
{
return a.h<b.h;
}
void built(int i,int l,int r)
{
tree[i].lc=l,tree[i].rc=r;
tree[i].len=tree[i].num=tree[i].rn=tree[i].ln=tree[i].cnt=0;
if(l==r-1)return;
int mid=(l+r)/2;
built(2*i,l,mid);
built(2*i+1,mid,r);
}
void update_len(int i)
{
if(tree[i].cnt)
{
tree[i].len=pos[tree[i].rc]-pos[tree[i].lc];
tree[i].num=1;
tree[i].ln=tree[i].rn=1;
}
else
{
tree[i].len=tree[2*i].len+tree[2*i+1].len;
tree[i].num=tree[2*i].num+tree[2*i+1].num;
if(tree[2*i].rn&&tree[2*i+1].ln)tree[i].num--;
tree[i].rn=tree[2*i+1].rn;
tree[i].ln=tree[2*i].ln;
}
}
void update(int i,char val)
{
if(pos[tree[i].lc]>tmpr||pos[tree[i].rc]<tmpl)return;
if(pos[tree[i].lc]>=tmpl&&pos[tree[i].rc]<=tmpr)
{
tree[i].cnt+=val;
update_len(i);
}
if(tree[i].lc==tree[i].rc-1)return;
update(2*i,val);
update(2*i+1,val);
update_len(i);
}
void scan()
{
int now=2*n;
int last=0,lh=line[2*n].h;
while(now)
{
ans+=tree[1].num*2*(lh-line[now].h);
lh=line[now].h;
tmpl=line[now].l,tmpr=line[now].r;
update(1,line[now].lab);
ans+=abs(tree[1].len-last);
last=tree[1].len;
--now;
}
}
int main()
{
while(scanf("%d",&n)!=EOF)
{
int x1,y1,x2,y2;
for(int i=1;i<=n;i++)
{
scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
//x1+=CONST,x2+=CONST,y1+=CONST,y2+=CONST;
line[i].l=x1,line[i].r=x2,line[i].h=y1,line[i].lab=1;
line[n+i].l=x1,line[n+i].r=x2,line[n+i].h=y2,line[n+i].lab=-1;
pos[i]=x1,pos[n+i]=x2;
}
sort(line+1,line+1+2*n,cmp);
sort(pos+1,pos+1+2*n);
m=1;
ans=0;
for(int i=2;i<=2*n;i++)
if(pos[i]!=pos[i-1])pos[++m]=pos[i];
built(1,1,m);
scan();
printf("%d\n",ans);
}
}