POJ1177 Picture

  1 #include <algorithm>
  2 #include <iostream>
  3 #include <cstdlib>
  4 #include <cstdio>
  5 const int N = 10000 + 11 ;
  6 using namespace std;
  7 int n ,li[N] , tot;
  8 struct id
  9 {
 10     int x,y1,x2,y2,flag;
 11 } line[N];
 12 struct a_seg_tree
 13 {
 14     struct a_tree
 15     {
 16         int l,r,cnt,qucnt,len,lenall,seg,mid;
 17         bool rbd,lbd ;
 18     } tree[N<<2];
 19     void build(int l,int r,int num) 
 20     {
 21         tree[num].l = l , tree[num].r = r;
 22         tree[num].lenall = tree[num].cnt = tree[num].seg = 0;
 23         int mid = l + ( (r - l )>>1),ii = num << 1 ;
 24         tree[num].len = li[r] - li[l];
 25         tree[num].mid = mid;
 26         if(r - l > 1)
 27         {
 28             build(l,mid,ii);
 29             build(mid,r,ii+1);
 30         }
 31     }
 32     void Update(int num)
 33     {
 34         if(tree[num].cnt > 0)
 35         {
 36             tree[num].lenall = tree[num].len;
 37             tree[num].seg = 1; 
 38             tree[num].lbd = tree[num].rbd = true ;
 39         }
 40         else if(tree[num].r-tree[num].l>1)
 41         {
 42             int ii = num << 1;
 43             tree[num].lenall = tree[ii].lenall + tree[ii+1].lenall;
 44             tree[num].lbd = tree[ii].lbd;
 45             tree[num].rbd = tree[ii+1].rbd;
 46             tree[num].seg = tree[ii].seg + tree[ii+1].seg - (tree[ii].rbd & tree[ii+1].lbd);
 47         }
 48         else
 49         {
 50             tree[num].lenall = tree[num].seg = 0;
 51             tree[num].lbd = tree[num].rbd = false;
 52         }
 53         
 54     }
 55     void Insert(int l,int r,int num)
 56     {
 57         if(l == tree[num].l && r == tree[num].r) ++tree[num].cnt;
 58         else
 59         {
 60             int mid = tree[num].mid,ii = num << 1;
 61             if(r <= mid) Insert(l,r,ii);
 62             else if(l >= mid) Insert(l,r,ii+1);
 63             else Insert(l,mid,ii),Insert(mid,r,ii+1);
 64         }
 65         Update(num);
 66     }
 67     void Delete(int l,int r,int num)
 68     {
 69         if(l == tree[num].l && r == tree[num].r)--tree[num].cnt;
 70         else
 71         {
 72             int mid = tree[num].mid,ii = num << 1;
 73             if(r <= mid)Delete(l,r,ii);
 74             else if(l>=mid)Delete(l,r,ii+1);
 75             else Delete(l,mid,ii),Delete(mid,r,ii+1);
 76         }
 77         Update(num);
 78     }
 79 }seg_tree;
 80 
 81 int cmp(id a,id b)
 82 {
 83     if(a.x == b.x)return a.flag > b.flag;
 84     return a.x < b.x;
 85 }
 86 
 87 
 88 void Init()
 89 {
 90     scanf("%d",&n);
 91     int x1,y1,x2,y2,i= 0;
 92     while(n--)
 93     {
 94         scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
 95         line[++i].x=x1,line[i].y1=y1,line[i].y2=y2,line[i].flag=1;li[i]=y1;
 96         line[++i].x=x2,line[i].y1=y1,line[i].y2=y2,line[i].flag=-1;li[i]=y2;
 97     }
 98     sort(li+1,li+1+i); n = i ;
 99     sort(line+1,line+1+i,cmp);
100     tot = 1 ;
101     for(int j = 2; j <= i ; ++j )
102         if(li[j] != li[tot])li[++tot] = li[j];
103 }
104 
105 int binary_search( int sum )
106 {
107     int l = 1 , r = tot;
108     while(l <= r)
109     {
110         int mid = l + ((r-l)>>1);
111         if(li[mid] == sum)return mid;
112         if(sum<li[mid])r = mid - 1;
113         else l = mid + 1;
114     }
115     return -1;
116 }
117 
118 void Solve()
119 {
120     seg_tree.build(1,tot,1);
121     int ans = 0 , pre = 0 ; 
122     for(int i = 1; i < n;++i)
123     {
124         int y1 = binary_search(line[i].y1) , y2 = binary_search(line[i].y2) ;    
125         if(line[i].flag == 1 )
126             seg_tree.Insert(y1,y2,1) ; 
127         else
128             seg_tree.Delete(y1,y2,1);
129         ans += seg_tree.tree[1].seg * (line[i+1].x-line[i].x) << 1 ;
130         ans += abs(seg_tree.tree[1].lenall-pre);
131         
132         pre = seg_tree.tree[1].lenall;
133     }
134     seg_tree.Delete(binary_search(line[n].y1),binary_search(line[n].y2),1);
135     ans += abs(seg_tree.tree[1].lenall - pre) ;
136     printf("%d\n",ans);
137 }
138 
139 int main()
140 {
141 //    freopen("picture.in","r",stdin);
142 //    freopen("picture.out","w",stdout);
143     Init();
144     Solve();
145     fclose(stdin);
146     fclose(stdout);
147     return 0 ;    
148 }