PO J 2528 Mayor's posters （线段树+离散化）

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 int flag;
 6 struct p
 7 {
 8     int x,d;
 9 };p s[24000];
10 bool com1(p A,p B)
11 {
12     return A.x<B.x;
13 }
14 bool com2(p A,p B)
15 {
16     if (A.d==B.d) return A.x<B.x;
17     return A.d>B.d;
18 }
19 struct pp
20 {
21     int l,r,v;
22 };pp tree[1000000];
23 void build(int l,int r,int p)
24 {
25     tree[p].l=l;
26     tree[p].r=r;
27     tree[p].v=0;
28     if (l==r) return ;
29     int m=(l+r)/2;
30     build(l,m,2*p);
31     build(m+1,r,2*p+1);
32     return ;
33 }
34 void find(int l,int r,int p)
35 {
36     if (tree[p].v) return ;
37     if (tree[p].l==l&&tree[p].r==r)
38     {
39         flag=1;
40         tree[p].v=1;
41         return ;
42     }
43     int m=(tree[p].l+tree[p].r)/2;
44     if (l>m) find(l,r,2*p+1);
45     else if (m>=r) find (l,r,2*p);
46     else
47     {
48         find(l,m,2*p);
49         find(m+1,r,2*p+1);
50     }
51     tree[p].v=tree[2*p].v&&tree[2*p+1].v;
52     return ;
53 }
54 int main()
55 {
56     int c,n,i,j,ans;
57     scanf("%d",&c);
58     while (c--)
59     {
60         scanf("%d",&n);
61         for (i=1;i<=2*n;i+=2)
62         {
63             scanf("%d%d",&s[i].x,&s[i+1].x);
64             s[i].d=s[i+1].d=i;
65         }
66         sort (s+1,s+2*n+1,com1);
67         int p1=0,p2=0;
68         for (i=1;i<=2*n;i++)
69         {
70             if (s[i].x==p1)
71                s[i].x=p2;
72             else
73             {
74                 p1=s[i].x;
75                 s[i].x=++p2;
76             }
77           //  printf("**%d**\n",s[i].x);
78         }
79         build(1,2*n,1);
80         ans=0;
81         sort(s+1,s+2*n+1,com2);
82         for (i=1;i<=2*n;i+=2)
83         {
84             flag=0;
85             find(s[i].x,s[i+1].x,1);
86           //  printf("**%d***%d**\n",s[i].x,s[i+1].x);
87             if (flag) ans++;
88         }
89         printf("%d\n",ans);
90     }
91     return 0;
92 }